diff --git a/packages/react-client/src/__tests__/ReactFlight-test.js b/packages/react-client/src/__tests__/ReactFlight-test.js
index b954f32ecd674..ef9864200588a 100644
--- a/packages/react-client/src/__tests__/ReactFlight-test.js
+++ b/packages/react-client/src/__tests__/ReactFlight-test.js
@@ -1957,8 +1957,8 @@ describe('ReactFlight', () => {
       });
       expect(ReactNoop).toMatchRenderedOutput(
         <>
-          <div prop="«S1»" />
-          <div prop="«S2»" />
+          <div prop="_S_1_" />
+          <div prop="_S_2_" />
         </>,
       );
     });
@@ -1981,8 +1981,8 @@ describe('ReactFlight', () => {
       });
       expect(ReactNoop).toMatchRenderedOutput(
         <>
-          <div prop="«fooS1»" />
-          <div prop="«fooS2»" />
+          <div prop="_fooS_1_" />
+          <div prop="_fooS_2_" />
         </>,
       );
     });
@@ -2021,8 +2021,8 @@ describe('ReactFlight', () => {
       assertLog(['ClientDoubler']);
       expect(ReactNoop).toMatchRenderedOutput(
         <>
-          <div prop="«S1»">«S1»</div>
-          <div prop="«S1»">«S1»</div>
+          <div prop="_S_1_">_S_1_</div>
+          <div prop="_S_1_">_S_1_</div>
         </>,
       );
     });
diff --git a/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js b/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js
index efa59d8605ed2..2b93c8f06e2b2 100644
--- a/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js
+++ b/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js
@@ -1553,7 +1553,7 @@ describe('ReactHooksInspectionIntegration', () => {
     expect(tree[0].id).toEqual(0);
     expect(tree[0].isStateEditable).toEqual(false);
     expect(tree[0].name).toEqual('Id');
-    expect(String(tree[0].value).startsWith('\u00ABr')).toBe(true);
+    expect(String(tree[0].value).startsWith('_r_')).toBe(true);
 
     expect(normalizeSourceLoc(tree)[1]).toMatchInlineSnapshot(`
       {
diff --git a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
index b4091511ee6b8..795a406690282 100644
--- a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
+++ b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
@@ -1082,7 +1082,7 @@ export function makeId(
 ): string {
   const idPrefix = resumableState.idPrefix;
 
-  let id = '\u00AB' + idPrefix + 'R' + treeId;
+  let id = '_' + idPrefix + 'R_' + treeId;
 
   // Unless this is the first id at this level, append a number at the end
   // that represents the position of this useId hook among all the useId
@@ -1091,7 +1091,7 @@ export function makeId(
     id += 'H' + localId.toString(32);
   }
 
-  return id + '\u00BB';
+  return id + '_';
 }
 
 function encodeHTMLTextNode(text: string): string {
@@ -5415,7 +5415,7 @@ function writeBlockingRenderInstruction(
 ): void {
   if (enableFizzBlockingRender) {
     const idPrefix = resumableState.idPrefix;
-    const shellId = '\u00AB' + idPrefix + 'R\u00BB';
+    const shellId = '_' + idPrefix + 'R_';
     writeChunk(destination, blockingRenderChunkStart);
     writeChunk(destination, stringToChunk(escapeTextForBrowser(shellId)));
     writeChunk(destination, blockingRenderChunkEnd);
@@ -5433,7 +5433,7 @@ function writeCompletedShellIdAttribute(
   }
   resumableState.instructions |= SentCompletedShellId;
   const idPrefix = resumableState.idPrefix;
-  const shellId = '\u00AB' + idPrefix + 'R\u00BB';
+  const shellId = '_' + idPrefix + 'R_';
   writeChunk(destination, completedShellIdAttributeStart);
   writeChunk(destination, stringToChunk(escapeTextForBrowser(shellId)));
   writeChunk(destination, attributeEnd);
@@ -5448,7 +5448,7 @@ function pushCompletedShellIdAttribute(
   }
   resumableState.instructions |= SentCompletedShellId;
   const idPrefix = resumableState.idPrefix;
-  const shellId = '\u00AB' + idPrefix + 'R\u00BB';
+  const shellId = '_' + idPrefix + 'R_';
   target.push(
     completedShellIdAttributeStart,
     stringToChunk(escapeTextForBrowser(shellId)),
diff --git a/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetInlineCodeStrings.js b/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetInlineCodeStrings.js
index e74e4bbe86b28..eacd86aa0687d 100644
--- a/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetInlineCodeStrings.js
+++ b/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetInlineCodeStrings.js
@@ -8,7 +8,7 @@ export const clientRenderBoundary =
 export const completeBoundary =
   '$RB=[];$RV=function(c){$RT=performance.now();for(var a=0;a<c.length;a+=2){var b=c[a],h=c[a+1],e=b.parentNode;if(e){var f=b.previousSibling,g=0;do{if(b&&8===b.nodeType){var d=b.data;if("/$"===d||"/&"===d)if(0===g)break;else g--;else"$"!==d&&"$?"!==d&&"$~"!==d&&"$!"!==d&&"&"!==d||g++}d=b.nextSibling;e.removeChild(b);b=d}while(b);for(;h.firstChild;)e.insertBefore(h.firstChild,b);f.data="$";f._reactRetry&&f._reactRetry()}}c.length=0};$RC=function(c,a){if(a=document.getElementById(a))if(a.parentNode.removeChild(a),c=document.getElementById(c))c.previousSibling.data="$~",$RB.push(c,a),2===$RB.length&&setTimeout($RV.bind(null,$RB),("number"!==typeof $RT?0:$RT)+300-performance.now())};';
 export const completeBoundaryUpgradeToViewTransitions =
-  '$RV=function(w,f){function h(a,d){var k=a.getAttribute(d);k&&(d=a.style,l.push(a,d.viewTransitionName,d.viewTransitionClass),"auto"!==k&&(d.viewTransitionClass=k),(a=a.getAttribute("vt-name"))||(a="\\u00abT"+F++ +"\\u00bb"),d.viewTransitionName=a,x=!0)}var x=!1,F=0,l=[];try{var e=document.__reactViewTransition;if(e){e.finished.finally($RV.bind(null,f));return}var m=new Map;for(e=1;e<f.length;e+=2)for(var g=f[e].querySelectorAll("[vt-share]"),c=0;c<g.length;c++){var b=g[c];m.set(b.getAttribute("vt-name"),b)}for(g=0;g<f.length;g+=2){var y=f[g],t=y.parentNode;if(t){var r=t.getBoundingClientRect();if(r.left||r.top||r.width||r.height){b=y;for(e=0;b;){if(8===b.nodeType){var p=b.data;if("/$"===p)if(0===e)break;else e--;else"$"!==p&&"$?"!==p&&"$~"!==p&&"$!"!==p||e++}else if(1===b.nodeType){c=b;var z=c.getAttribute("vt-name"),u=m.get(z);h(c,u?"vt-share":"vt-exit");u&&(h(u,"vt-share"),m.set(z,null));var A=c.querySelectorAll("[vt-share]");for(c=0;c<A.length;c++){var B=A[c],C=B.getAttribute("vt-name"),D=m.get(C);\nD&&(h(B,"vt-share"),h(D,"vt-share"),m.set(C,null))}}b=b.nextSibling}for(var q=f[g+1].firstElementChild;q;)null!==m.get(q.getAttribute("vt-name"))&&h(q,"vt-enter"),q=q.nextElementSibling;b=t;do for(var n=b.firstElementChild;n;){var E=n.getAttribute("vt-update");E&&"none"!==E&&!l.includes(n)&&h(n,"vt-update");n=n.nextElementSibling}while((b=b.parentNode)&&1===b.nodeType&&"none"!==b.getAttribute("vt-update"))}}}if(x){var v=document.__reactViewTransition=document.startViewTransition({update:function(){w(f,\ndocument.documentElement.clientHeight);return Promise.race([document.fonts.ready,new Promise(function(a){return setTimeout(a,500)})])},types:[]});v.ready.finally(function(){for(var a=l.length-3;0<=a;a-=3){var d=l[a],k=d.style;k.viewTransitionName=l[a+1];k.viewTransitionClass=l[a+1];""===d.getAttribute("style")&&d.removeAttribute("style")}});v.finished.finally(function(){document.__reactViewTransition===v&&(document.__reactViewTransition=null)});$RB=[];return}}catch(a){}w(f)}.bind(null,$RV);';
+  '$RV=function(w,f){function h(a,d){var k=a.getAttribute(d);k&&(d=a.style,l.push(a,d.viewTransitionName,d.viewTransitionClass),"auto"!==k&&(d.viewTransitionClass=k),(a=a.getAttribute("vt-name"))||(a="_T_"+F++ +"_"),d.viewTransitionName=a,x=!0)}var x=!1,F=0,l=[];try{var e=document.__reactViewTransition;if(e){e.finished.finally($RV.bind(null,f));return}var m=new Map;for(e=1;e<f.length;e+=2)for(var g=f[e].querySelectorAll("[vt-share]"),c=0;c<g.length;c++){var b=g[c];m.set(b.getAttribute("vt-name"),b)}for(g=0;g<f.length;g+=2){var y=f[g],t=y.parentNode;if(t){var r=t.getBoundingClientRect();if(r.left||r.top||r.width||r.height){b=y;for(e=0;b;){if(8===b.nodeType){var p=b.data;if("/$"===p)if(0===e)break;else e--;else"$"!==p&&"$?"!==p&&"$~"!==p&&"$!"!==p||e++}else if(1===b.nodeType){c=b;var z=c.getAttribute("vt-name"),u=m.get(z);h(c,u?"vt-share":"vt-exit");u&&(h(u,"vt-share"),m.set(z,null));var A=c.querySelectorAll("[vt-share]");for(c=0;c<A.length;c++){var B=A[c],C=B.getAttribute("vt-name"),D=m.get(C);\nD&&(h(B,"vt-share"),h(D,"vt-share"),m.set(C,null))}}b=b.nextSibling}for(var q=f[g+1].firstElementChild;q;)null!==m.get(q.getAttribute("vt-name"))&&h(q,"vt-enter"),q=q.nextElementSibling;b=t;do for(var n=b.firstElementChild;n;){var E=n.getAttribute("vt-update");E&&"none"!==E&&!l.includes(n)&&h(n,"vt-update");n=n.nextElementSibling}while((b=b.parentNode)&&1===b.nodeType&&"none"!==b.getAttribute("vt-update"))}}}if(x){var v=document.__reactViewTransition=document.startViewTransition({update:function(){w(f,\ndocument.documentElement.clientHeight);return Promise.race([document.fonts.ready,new Promise(function(a){return setTimeout(a,500)})])},types:[]});v.ready.finally(function(){for(var a=l.length-3;0<=a;a-=3){var d=l[a],k=d.style;k.viewTransitionName=l[a+1];k.viewTransitionClass=l[a+1];""===d.getAttribute("style")&&d.removeAttribute("style")}});v.finished.finally(function(){document.__reactViewTransition===v&&(document.__reactViewTransition=null)});$RB=[];return}}catch(a){}w(f)}.bind(null,$RV);';
 export const completeBoundaryWithStyles =
   '$RM=new Map;$RR=function(n,w,p){function u(q){this._p=null;q()}for(var r=new Map,t=document,h,b,e=t.querySelectorAll("link[data-precedence],style[data-precedence]"),v=[],k=0;b=e[k++];)"not all"===b.getAttribute("media")?v.push(b):("LINK"===b.tagName&&$RM.set(b.getAttribute("href"),b),r.set(b.dataset.precedence,h=b));e=0;b=[];var l,a;for(k=!0;;){if(k){var f=p[e++];if(!f){k=!1;e=0;continue}var c=!1,m=0;var d=f[m++];if(a=$RM.get(d)){var g=a._p;c=!0}else{a=t.createElement("link");a.href=d;a.rel=\n"stylesheet";for(a.dataset.precedence=l=f[m++];g=f[m++];)a.setAttribute(g,f[m++]);g=a._p=new Promise(function(q,x){a.onload=u.bind(a,q);a.onerror=u.bind(a,x)});$RM.set(d,a)}d=a.getAttribute("media");!g||d&&!matchMedia(d).matches||b.push(g);if(c)continue}else{a=v[e++];if(!a)break;l=a.getAttribute("data-precedence");a.removeAttribute("media")}c=r.get(l)||h;c===h&&(h=a);r.set(l,a);c?c.parentNode.insertBefore(a,c.nextSibling):(c=t.head,c.insertBefore(a,c.firstChild))}if(p=document.getElementById(n))p.previousSibling.data=\n"$~";Promise.all(b).then($RC.bind(null,n,w),$RX.bind(null,n,"CSS failed to load"))};';
 export const completeSegment =
diff --git a/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetShared.js b/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetShared.js
index bb8c0059c8b49..475005d1aca43 100644
--- a/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetShared.js
+++ b/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetShared.js
@@ -111,7 +111,7 @@ export function revealCompletedBoundariesWithViewTransitions(
       // TODO: We don't have a prefix to pick from here but maybe we don't need it
       // since it's only applicable temporarily during this specific animation.
       const idPrefix = '';
-      name = '\u00AB' + idPrefix + 'T' + autoNameIdx++ + '\u00BB';
+      name = '_' + idPrefix + 'T_' + autoNameIdx++ + '_';
     }
     elementStyle['viewTransitionName'] = name;
     shouldStartViewTransition = true;
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
index 02d7b1dad2fd5..d5f635f964934 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
@@ -3587,7 +3587,7 @@ describe('ReactDOMFizzServer', () => {
           ? '<script src="react-dom-bindings/src/server/ReactDOMServerExternalRuntime.js" async=""></script>'
           : '') +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render">'
+          ? '<link rel="expect" href="#_R_" blocking="render">'
           : ''),
     );
   });
@@ -4197,7 +4197,7 @@ describe('ReactDOMFizzServer', () => {
         renderOptions.unstable_externalRuntimeSrc,
       ).map(n => n.outerHTML),
     ).toEqual([
-      '<script src="foo" id="«R»" async=""></script>',
+      '<script src="foo" id="_R_" async=""></script>',
       '<script src="bar" async=""></script>',
       '<script src="baz" integrity="qux" async=""></script>',
       '<script type="module" src="quux" async=""></script>',
@@ -4284,7 +4284,7 @@ describe('ReactDOMFizzServer', () => {
         renderOptions.unstable_externalRuntimeSrc,
       ).map(n => n.outerHTML),
     ).toEqual([
-      '<script src="foo" id="«R»" async=""></script>',
+      '<script src="foo" id="_R_" async=""></script>',
       '<script src="bar" async=""></script>',
       '<script src="baz" crossorigin="" async=""></script>',
       '<script src="qux" crossorigin="" async=""></script>',
@@ -4523,11 +4523,11 @@ describe('ReactDOMFizzServer', () => {
     expect(document.documentElement.innerHTML).toEqual(
       '<head><script src="react-dom-bindings/src/server/ReactDOMServerExternalRuntime.js" async=""></script>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render">'
+          ? '<link rel="expect" href="#_R_" blocking="render">'
           : '') +
         '</head><body><p>hello world!</p>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '') +
         '</body>',
     );
@@ -6519,11 +6519,11 @@ describe('ReactDOMFizzServer', () => {
           ? '<script src="react-dom-bindings/src/server/ReactDOMServerExternalRuntime.js" async=""></script>'
           : '') +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render">'
+          ? '<link rel="expect" href="#_R_" blocking="render">'
           : '') +
         '</head><body><script>try { foo() } catch (e) {} ;</script>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '') +
         '</body></html>',
     );
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServerBrowser-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServerBrowser-test.js
index 1755544a5d35d..bc96750d46038 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServerBrowser-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServerBrowser-test.js
@@ -73,7 +73,7 @@ describe('ReactDOMFizzServerBrowser', () => {
     const result = await readResult(stream);
     if (gate(flags => flags.enableFizzBlockingRender)) {
       expect(result).toMatchInlineSnapshot(
-        `"<!DOCTYPE html><html><head><link rel="expect" href="#«R»" blocking="render"/></head><body>hello world<template id="«R»"></template></body></html>"`,
+        `"<!DOCTYPE html><html><head><link rel="expect" href="#_R_" blocking="render"/></head><body>hello world<template id="_R_"></template></body></html>"`,
       );
     } else {
       expect(result).toMatchInlineSnapshot(
@@ -92,7 +92,7 @@ describe('ReactDOMFizzServerBrowser', () => {
     );
     const result = await readResult(stream);
     expect(result).toMatchInlineSnapshot(
-      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="«R»">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
+      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="_R_">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
     );
   });
 
@@ -524,11 +524,11 @@ describe('ReactDOMFizzServerBrowser', () => {
     expect(result).toEqual(
       '<!DOCTYPE html><html><head>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render"/>'
+          ? '<link rel="expect" href="#_R_" blocking="render"/>'
           : '') +
         '<title>foo</title></head><body>bar' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '') +
         '</body></html>',
     );
@@ -548,7 +548,7 @@ describe('ReactDOMFizzServerBrowser', () => {
     expect(result).toMatchInlineSnapshot(
       // TODO: remove interpolation because it prevents snapshot updates.
       // eslint-disable-next-line jest/no-interpolation-in-snapshots
-      `"<link rel="preload" as="script" fetchPriority="low" nonce="R4nd0m" href="init.js"/><link rel="modulepreload" fetchPriority="low" nonce="R4nd0m" href="init.mjs"/><div>hello world</div><script nonce="${nonce}" id="«R»">INIT();</script><script src="init.js" nonce="${nonce}" async=""></script><script type="module" src="init.mjs" nonce="${nonce}" async=""></script>"`,
+      `"<link rel="preload" as="script" fetchPriority="low" nonce="R4nd0m" href="init.js"/><link rel="modulepreload" fetchPriority="low" nonce="R4nd0m" href="init.mjs"/><div>hello world</div><script nonce="${nonce}" id="_R_">INIT();</script><script src="init.js" nonce="${nonce}" async=""></script><script type="module" src="init.mjs" nonce="${nonce}" async=""></script>"`,
     );
   });
 
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServerEdge-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServerEdge-test.js
index 801baa9678af4..c5cbe8bb85dc2 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServerEdge-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServerEdge-test.js
@@ -73,7 +73,7 @@ describe('ReactDOMFizzServerEdge', () => {
 
     if (gate(flags => flags.enableFizzBlockingRender)) {
       expect(result).toMatchInlineSnapshot(
-        `"<!DOCTYPE html><html><head><link rel="expect" href="#«R»" blocking="render"/></head><body><main>hello</main><template id="«R»"></template></body></html>"`,
+        `"<!DOCTYPE html><html><head><link rel="expect" href="#_R_" blocking="render"/></head><body><main>hello</main><template id="_R_"></template></body></html>"`,
       );
     } else {
       expect(result).toMatchInlineSnapshot(
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServerNode-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServerNode-test.js
index 198ccb4f8f6a5..7db7a669c3efd 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServerNode-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServerNode-test.js
@@ -95,7 +95,7 @@ describe('ReactDOMFizzServerNode', () => {
     // with Float, we emit empty heads if they are elided when rendering <html>
     if (gate(flags => flags.enableFizzBlockingRender)) {
       expect(output.result).toMatchInlineSnapshot(
-        `"<!DOCTYPE html><html><head><link rel="expect" href="#«R»" blocking="render"/></head><body>hello world<template id="«R»"></template></body></html>"`,
+        `"<!DOCTYPE html><html><head><link rel="expect" href="#_R_" blocking="render"/></head><body>hello world<template id="_R_"></template></body></html>"`,
       );
     } else {
       expect(output.result).toMatchInlineSnapshot(
@@ -118,7 +118,7 @@ describe('ReactDOMFizzServerNode', () => {
       pipe(writable);
     });
     expect(output.result).toMatchInlineSnapshot(
-      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="«R»">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
+      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="_R_">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
     );
   });
 
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzStaticBrowser-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzStaticBrowser-test.js
index fc01dcb156643..478bed90a3a0d 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzStaticBrowser-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzStaticBrowser-test.js
@@ -186,7 +186,7 @@ describe('ReactDOMFizzStaticBrowser', () => {
     const prelude = await readContent(result.prelude);
     if (gate(flags => flags.enableFizzBlockingRender)) {
       expect(prelude).toMatchInlineSnapshot(
-        `"<!DOCTYPE html><html><head><link rel="expect" href="#«R»" blocking="render"/></head><body>hello world<template id="«R»"></template></body></html>"`,
+        `"<!DOCTYPE html><html><head><link rel="expect" href="#_R_" blocking="render"/></head><body>hello world<template id="_R_"></template></body></html>"`,
       );
     } else {
       expect(prelude).toMatchInlineSnapshot(
@@ -205,7 +205,7 @@ describe('ReactDOMFizzStaticBrowser', () => {
     );
     const prelude = await readContent(result.prelude);
     expect(prelude).toMatchInlineSnapshot(
-      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="«R»">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
+      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="_R_">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
     );
   });
 
@@ -1434,12 +1434,12 @@ describe('ReactDOMFizzStaticBrowser', () => {
       '<!DOCTYPE html><html lang="en"><head>' +
         '<link rel="stylesheet" href="my-style" data-precedence="high"/>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render"/>'
+          ? '<link rel="expect" href="#_R_" blocking="render"/>'
           : '') +
         '</head>' +
         '<body>Hello' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '') +
         '</body></html>',
     );
@@ -1487,8 +1487,8 @@ describe('ReactDOMFizzStaticBrowser', () => {
     expect(await readContent(content)).toBe(
       '<!DOCTYPE html><html lang="en"><head>' +
         '<link rel="stylesheet" href="my-style" data-precedence="high"/>' +
-        '<link rel="expect" href="#«R»" blocking="render"/></head>' +
-        '<body>Hello<template id="«R»"></template></body></html>',
+        '<link rel="expect" href="#_R_" blocking="render"/></head>' +
+        '<body>Hello<template id="_R_"></template></body></html>',
     );
   });
 
@@ -1539,8 +1539,8 @@ describe('ReactDOMFizzStaticBrowser', () => {
     expect(await readContent(content)).toBe(
       '<!DOCTYPE html><html><head>' +
         '<link rel="stylesheet" href="my-style" data-precedence="high"/>' +
-        '<link rel="expect" href="#«R»" blocking="render"/></head>' +
-        '<body><div>Hello</div><template id="«R»"></template></body></html>',
+        '<link rel="expect" href="#_R_" blocking="render"/></head>' +
+        '<body><div>Hello</div><template id="_R_"></template></body></html>',
     );
   });
 
@@ -1622,8 +1622,8 @@ describe('ReactDOMFizzStaticBrowser', () => {
     let result = decoder.decode(value, {stream: true});
 
     expect(result).toBe(
-      '<!DOCTYPE html><html><head><link rel="expect" href="#«R»" blocking="render"/></head>' +
-        '<body>hello<!--$?--><template id="B:1"></template><!--/$--><script id="«R»">requestAnimationFrame(function(){$RT=performance.now()});</script>',
+      '<!DOCTYPE html><html><head><link rel="expect" href="#_R_" blocking="render"/></head>' +
+        '<body>hello<!--$?--><template id="B:1"></template><!--/$--><script id="_R_">requestAnimationFrame(function(){$RT=performance.now()});</script>',
     );
 
     await 1;
@@ -1647,8 +1647,8 @@ describe('ReactDOMFizzStaticBrowser', () => {
     const slice = result.slice(0, instructionIndex + '$RX'.length);
 
     expect(slice).toBe(
-      '<!DOCTYPE html><html><head><link rel="expect" href="#«R»" blocking="render"/></head>' +
-        '<body>hello<!--$?--><template id="B:1"></template><!--/$--><script id="«R»">requestAnimationFrame(function(){$RT=performance.now()});</script>' +
+      '<!DOCTYPE html><html><head><link rel="expect" href="#_R_" blocking="render"/></head>' +
+        '<body>hello<!--$?--><template id="B:1"></template><!--/$--><script id="_R_">requestAnimationFrame(function(){$RT=performance.now()});</script>' +
         '<div hidden id="S:1">world<!-- --></div><script>$RX',
     );
   });
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzStaticNode-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzStaticNode-test.js
index 3aa7a70cb80df..99a417657b8b2 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzStaticNode-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzStaticNode-test.js
@@ -65,7 +65,7 @@ describe('ReactDOMFizzStaticNode', () => {
     const prelude = await readContent(result.prelude);
     if (gate(flags => flags.enableFizzBlockingRender)) {
       expect(prelude).toMatchInlineSnapshot(
-        `"<!DOCTYPE html><html><head><link rel="expect" href="#«R»" blocking="render"/></head><body>hello world<template id="«R»"></template></body></html>"`,
+        `"<!DOCTYPE html><html><head><link rel="expect" href="#_R_" blocking="render"/></head><body>hello world<template id="_R_"></template></body></html>"`,
       );
     } else {
       expect(prelude).toMatchInlineSnapshot(
@@ -86,7 +86,7 @@ describe('ReactDOMFizzStaticNode', () => {
     );
     const prelude = await readContent(result.prelude);
     expect(prelude).toMatchInlineSnapshot(
-      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="«R»">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
+      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="_R_">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
     );
   });
 
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzViewTransition-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzViewTransition-test.js
index 3077fb5b3f82e..6ca7cfd4dc094 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzViewTransition-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzViewTransition-test.js
@@ -303,7 +303,7 @@ describe('ReactDOMFizzViewTransition', () => {
 
     expect(getVisibleChildren(container)).toEqual(
       <div>
-        <div vt-name="«R0»" vt-update="auto" vt-share="auto">
+        <div vt-name="_R_0_" vt-update="auto" vt-share="auto">
           <span vt-update="auto">Loading</span>
         </div>
       </div>,
@@ -321,7 +321,7 @@ describe('ReactDOMFizzViewTransition', () => {
 
     expect(getVisibleChildren(container)).toEqual(
       <div>
-        <div vt-name="«R0»" vt-update="auto" vt-share="auto">
+        <div vt-name="_R_0_" vt-update="auto" vt-share="auto">
           <span vt-update="auto">Content</span>
         </div>
       </div>,
diff --git a/packages/react-dom/src/__tests__/ReactDOMFloat-test.js b/packages/react-dom/src/__tests__/ReactDOMFloat-test.js
index e3c3fb41284eb..6436f1898b798 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFloat-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFloat-test.js
@@ -707,12 +707,12 @@ describe('ReactDOMFloat', () => {
           ? '<script src="react-dom/unstable_server-external-runtime" async=""></script>'
           : '') +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render"/>'
+          ? '<link rel="expect" href="#_R_" blocking="render"/>'
           : '') +
         '<title>foo</title></head>' +
         '<body>bar' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : ''),
       '</body></html>',
     ]);
diff --git a/packages/react-dom/src/__tests__/ReactDOMLegacyFloat-test.js b/packages/react-dom/src/__tests__/ReactDOMLegacyFloat-test.js
index f6d868c84135a..2c4972245cd5b 100644
--- a/packages/react-dom/src/__tests__/ReactDOMLegacyFloat-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMLegacyFloat-test.js
@@ -36,11 +36,11 @@ describe('ReactDOMFloat', () => {
     expect(result).toEqual(
       '<html><head><meta charSet="utf-8"/>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render"/>'
+          ? '<link rel="expect" href="#_R_" blocking="render"/>'
           : '') +
         '<title>title</title><script src="foo"></script></head>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '') +
         '</html>',
     );
diff --git a/packages/react-dom/src/__tests__/ReactDOMUseId-test.js b/packages/react-dom/src/__tests__/ReactDOMUseId-test.js
index 7738994fb1e1e..895c2f9b0dae7 100644
--- a/packages/react-dom/src/__tests__/ReactDOMUseId-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMUseId-test.js
@@ -96,7 +96,7 @@ describe('useId', () => {
   }
 
   function normalizeTreeIdForTesting(id) {
-    const result = id.match(/\u00AB(R|r)([a-z0-9]*)(H([0-9]*))?\u00BB/);
+    const result = id.match(/_(R|r)_([a-z0-9]*)(H([0-9]*))?_/);
     if (result === undefined) {
       throw new Error('Invalid id format');
     }
@@ -285,7 +285,7 @@ describe('useId', () => {
     // 'R:' prefix, and the first character after that, which may not correspond
     // to a complete set of 5 bits.
     //
-    // Example: «Rclalalalalalalala...:
+    // Example: _Rclalalalalalalala...:
     //
     // We can use this pattern to test large ids that exceed the bitwise
     // safe range (32 bits). The algorithm should theoretically support ids
@@ -320,8 +320,8 @@ describe('useId', () => {
 
     // Confirm that every id matches the expected pattern
     for (let i = 0; i < divs.length; i++) {
-      // Example: «Rclalalalalalalala...:
-      expect(divs[i].id).toMatch(/^\u00ABR.(((al)*a?)((la)*l?))*\u00BB$/);
+      // Example: _Rclalalalalalalala...:
+      expect(divs[i].id).toMatch(/^_R_.(((al)*a?)((la)*l?))*_$/);
     }
   });
 
@@ -345,7 +345,7 @@ describe('useId', () => {
       <div
         id="container"
       >
-        «R0», «R0H1», «R0H2»
+        _R_0_, _R_0H1_, _R_0H2_
       </div>
     `);
   });
@@ -370,7 +370,7 @@ describe('useId', () => {
       <div
         id="container"
       >
-        «R0»
+        _R_0_
       </div>
     `);
   });
@@ -608,10 +608,10 @@ describe('useId', () => {
         id="container"
       >
         <div>
-          «custom-prefix-R1»
+          _custom-prefix-R_1_
         </div>
         <div>
-          «custom-prefix-R2»
+          _custom-prefix-R_2_
         </div>
       </div>
     `);
@@ -625,13 +625,13 @@ describe('useId', () => {
         id="container"
       >
         <div>
-          «custom-prefix-R1»
+          _custom-prefix-R_1_
         </div>
         <div>
-          «custom-prefix-R2»
+          _custom-prefix-R_2_
         </div>
         <div>
-          «custom-prefix-r0»
+          _custom-prefix-r_0_
         </div>
       </div>
     `);
@@ -672,11 +672,11 @@ describe('useId', () => {
         id="container"
       >
         <div>
-          «R0»
+          _R_0_
           <!-- -->
            
           <div>
-            «R7»
+            _R_7_
           </div>
         </div>
       </div>
@@ -690,11 +690,11 @@ describe('useId', () => {
         id="container"
       >
         <div>
-          «R0»
+          _R_0_
           <!-- -->
            
           <div>
-            «R7»
+            _R_7_
           </div>
         </div>
       </div>
diff --git a/packages/react-dom/src/__tests__/ReactRenderDocument-test.js b/packages/react-dom/src/__tests__/ReactRenderDocument-test.js
index 3501f1bd92af7..9a485f8ddd0f4 100644
--- a/packages/react-dom/src/__tests__/ReactRenderDocument-test.js
+++ b/packages/react-dom/src/__tests__/ReactRenderDocument-test.js
@@ -80,7 +80,7 @@ describe('rendering React components at document', () => {
       expect(testDocument.body.innerHTML).toBe(
         'Hello world' +
           (gate(flags => flags.enableFizzBlockingRender)
-            ? '<template id="«R»"></template>'
+            ? '<template id="_R_"></template>'
             : ''),
       );
 
@@ -90,7 +90,7 @@ describe('rendering React components at document', () => {
       expect(testDocument.body.innerHTML).toBe(
         'Hello moon' +
           (gate(flags => flags.enableFizzBlockingRender)
-            ? '<template id="«R»"></template>'
+            ? '<template id="_R_"></template>'
             : ''),
       );
 
@@ -120,7 +120,7 @@ describe('rendering React components at document', () => {
       expect(testDocument.body.innerHTML).toBe(
         'Hello world' +
           (gate(flags => flags.enableFizzBlockingRender)
-            ? '<template id="«R»"></template>'
+            ? '<template id="_R_"></template>'
             : ''),
       );
 
@@ -135,12 +135,12 @@ describe('rendering React components at document', () => {
       expect(testDocument.body).toBe(originalBody);
       expect(originalBody.innerHTML).toBe(
         gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '',
       );
       expect(originalHead.innerHTML).toBe(
         gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render">'
+          ? '<link rel="expect" href="#_R_" blocking="render">'
           : '',
       );
     });
@@ -183,7 +183,7 @@ describe('rendering React components at document', () => {
       expect(testDocument.body.innerHTML).toBe(
         'Hello world' +
           (gate(flags => flags.enableFizzBlockingRender)
-            ? '<template id="«R»"></template>'
+            ? '<template id="_R_"></template>'
             : ''),
       );
 
@@ -193,7 +193,7 @@ describe('rendering React components at document', () => {
 
       expect(testDocument.body.innerHTML).toBe(
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '') + 'Goodbye world',
       );
     });
@@ -227,7 +227,7 @@ describe('rendering React components at document', () => {
       expect(testDocument.body.innerHTML).toBe(
         'Hello world' +
           (gate(flags => flags.enableFizzBlockingRender)
-            ? '<template id="«R»"></template>'
+            ? '<template id="_R_"></template>'
             : ''),
       );
     });
@@ -366,7 +366,7 @@ describe('rendering React components at document', () => {
           ? 'Hello world'
           : 'Goodbye world' +
               (gate(flags => flags.enableFizzBlockingRender)
-                ? '<template id="«R»"></template>'
+                ? '<template id="_R_"></template>'
                 : ''),
       );
     });
diff --git a/packages/react-reconciler/src/ReactFiberHooks.js b/packages/react-reconciler/src/ReactFiberHooks.js
index fd3451f406d41..1740ee0a8600a 100644
--- a/packages/react-reconciler/src/ReactFiberHooks.js
+++ b/packages/react-reconciler/src/ReactFiberHooks.js
@@ -3446,7 +3446,7 @@ function mountId(): string {
     const treeId = getTreeId();
 
     // Use a captial R prefix for server-generated ids.
-    id = '\u00AB' + identifierPrefix + 'R' + treeId;
+    id = '_' + identifierPrefix + 'R_' + treeId;
 
     // Unless this is the first id at this level, append a number at the end
     // that represents the position of this useId hook among all the useId
@@ -3456,16 +3456,11 @@ function mountId(): string {
       id += 'H' + localId.toString(32);
     }
 
-    id += '\u00BB';
+    id += '_';
   } else {
     // Use a lowercase r prefix for client-generated ids.
     const globalClientId = globalClientIdCounter++;
-    id =
-      '\u00AB' +
-      identifierPrefix +
-      'r' +
-      globalClientId.toString(32) +
-      '\u00BB';
+    id = '_' + identifierPrefix + 'r_' + globalClientId.toString(32) + '_';
   }
 
   hook.memoizedState = id;
diff --git a/packages/react-reconciler/src/ReactFiberViewTransitionComponent.js b/packages/react-reconciler/src/ReactFiberViewTransitionComponent.js
index cda13a174a3aa..37768bcccbd31 100644
--- a/packages/react-reconciler/src/ReactFiberViewTransitionComponent.js
+++ b/packages/react-reconciler/src/ReactFiberViewTransitionComponent.js
@@ -41,7 +41,7 @@ export function getViewTransitionName(
   const identifierPrefix = root.identifierPrefix;
   const globalClientId = globalClientIdCounter++;
   const name =
-    '\u00AB' + identifierPrefix + 't' + globalClientId.toString(32) + '\u00BB';
+    '_' + identifierPrefix + 't_' + globalClientId.toString(32) + '_';
   instance.autoName = name;
   return name;
 }
diff --git a/packages/react-server-dom-fb/src/__tests__/ReactDOMServerFB-test.internal.js b/packages/react-server-dom-fb/src/__tests__/ReactDOMServerFB-test.internal.js
index 6d022ceb26c17..32284b0f68de6 100644
--- a/packages/react-server-dom-fb/src/__tests__/ReactDOMServerFB-test.internal.js
+++ b/packages/react-server-dom-fb/src/__tests__/ReactDOMServerFB-test.internal.js
@@ -59,7 +59,7 @@ describe('ReactDOMServerFB', () => {
     });
     const result = readResult(stream);
     expect(result).toMatchInlineSnapshot(
-      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="«R»">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
+      `"<link rel="preload" as="script" fetchPriority="low" href="init.js"/><link rel="modulepreload" fetchPriority="low" href="init.mjs"/><div>hello world</div><script id="_R_">INIT();</script><script src="init.js" async=""></script><script type="module" src="init.mjs" async=""></script>"`,
     );
   });
 
diff --git a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js
index 0b5f3b60164fc..442f0c5e08bab 100644
--- a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js
+++ b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js
@@ -1909,12 +1909,12 @@ describe('ReactFlightDOM', () => {
       '<!DOCTYPE html><html><head><link rel="preload" href="before1" as="style"/>' +
         '<link rel="preload" href="after1" as="style"/>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render"/>'
+          ? '<link rel="expect" href="#_R_" blocking="render"/>'
           : '') +
         '</head>' +
         '<body><p>hello world</p>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '') +
         '</body></html>',
     );
@@ -1922,12 +1922,12 @@ describe('ReactFlightDOM', () => {
       '<!DOCTYPE html><html><head><link rel="preload" href="before2" as="style"/>' +
         '<link rel="preload" href="after2" as="style"/>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render"/>'
+          ? '<link rel="expect" href="#_R_" blocking="render"/>'
           : '') +
         '</head>' +
         '<body><p>hello world</p>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '') +
         '</body></html>',
     );
diff --git a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js
index 32ad8c7a5b21a..8670f606ba75a 100644
--- a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js
+++ b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js
@@ -1888,12 +1888,12 @@ describe('ReactFlightDOMBrowser', () => {
     expect(content).toEqual(
       '<!DOCTYPE html><html><head>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<link rel="expect" href="#«R»" blocking="render"/>'
+          ? '<link rel="expect" href="#_R_" blocking="render"/>'
           : '') +
         '</head>' +
         '<body><p>hello world</p>' +
         (gate(flags => flags.enableFizzBlockingRender)
-          ? '<template id="«R»"></template>'
+          ? '<template id="_R_"></template>'
           : '') +
         '</body></html>',
     );
diff --git a/packages/react-server/src/ReactFlightHooks.js b/packages/react-server/src/ReactFlightHooks.js
index 442f6207a9c2c..c5ffc5dd70342 100644
--- a/packages/react-server/src/ReactFlightHooks.js
+++ b/packages/react-server/src/ReactFlightHooks.js
@@ -120,13 +120,7 @@ function useId(): string {
   }
   const id = currentRequest.identifierCount++;
   // use 'S' for Flight components to distinguish from 'R' and 'r' in Fizz/Client
-  return (
-    '\u00AB' +
-    currentRequest.identifierPrefix +
-    'S' +
-    id.toString(32) +
-    '\u00BB'
-  );
+  return '_' + currentRequest.identifierPrefix + 'S_' + id.toString(32) + '_';
 }
 
 function use<T>(usable: Usable<T>): T {