diff --git a/src/lib/merge-classlist.ts b/src/lib/merge-classlist.ts
index fa18139..de1142b 100644
--- a/src/lib/merge-classlist.ts
+++ b/src/lib/merge-classlist.ts
@@ -27,16 +27,15 @@ export function mergeClassList(classList: string, configUtils: ConfigUtils) {
                     maybePostfixModifierPosition,
                 } = parseClassName(originalClassName)
 
+                let hasPostfixModifier = Boolean(maybePostfixModifierPosition)
                 let classGroupId = getClassGroupId(
-                    maybePostfixModifierPosition
+                    hasPostfixModifier
                         ? baseClassName.substring(0, maybePostfixModifierPosition)
                         : baseClassName,
                 )
 
-                let hasPostfixModifier = Boolean(maybePostfixModifierPosition)
-
                 if (!classGroupId) {
-                    if (!maybePostfixModifierPosition) {
+                    if (!hasPostfixModifier) {
                         return {
                             isTailwindClass: false as const,
                             originalClassName,
diff --git a/src/lib/types.ts b/src/lib/types.ts
index def9f59..b79cf84 100644
--- a/src/lib/types.ts
+++ b/src/lib/types.ts
@@ -20,7 +20,8 @@ interface ConfigStatic {
      */
     separator: string
     /**
-     * Allows to customize parsing of individual class names.
+     * Allows to customize parsing of individual classes passed to `twMerge`.
+     * All classes passed to `twMerge` outside of cache hits are passed to this function before it is determined whether the class is a valid Tailwind CSS class.
      *
      * This is an experimental feature and may introduce breaking changes in any minor version update.
      */
@@ -28,7 +29,7 @@ interface ConfigStatic {
 }
 
 /**
- * Type of param passed to experimentalParseClassName function.
+ * Type of param passed to the `experimentalParseClassName` function.
  *
  * This is an experimental feature and may introduce breaking changes in any minor version update.
  */
@@ -38,14 +39,39 @@ export interface ExperimentalParseClassNameParam {
 }
 
 /**
- * Type of the result returned by experimentalParseClassName function.
+ * Type of the result returned by the `experimentalParseClassName` function.
  *
  * This is an experimental feature and may introduce breaking changes in any minor version update.
  */
 export interface ExperimentalParsedClassName {
+    /**
+     * Modifiers of the class in the order they appear in the class.
+     *
+     * @example ['hover', 'dark'] // for `hover:dark:bg-gray-100`
+     */
     modifiers: string[]
+    /**
+     * Whether the class has an `!important` modifier.
+     *
+     * @example true // for `hover:dark:!bg-gray-100`
+     */
     hasImportantModifier: boolean
+    /**
+     * Base class without preceding modifiers.
+     *
+     * @example 'bg-gray-100' // for `hover:dark:bg-gray-100`
+     */
     baseClassName: string
+    /**
+     * Index position of a possible postfix modifier in the class.
+     * If the class has no postfix modifier, this is `undefined`.
+     *
+     * This property is prefixed with "maybe" because tailwind-merge does not know whether something is a postfix modifier or part of the base class since it's possible to configure Tailwind CSS classes which include a `/` in the base class name.
+     *
+     * If a `maybePostfixModifierPosition` is present, tailwind-merge first tries to match the `baseClassName` without the possible postfix modifier to a class group. If tht fails, it tries again with the possible postfix modifier.
+     *
+     * @example 11 // for `bg-gray-100/50`
+     */
     maybePostfixModifierPosition: number | undefined
 }