diff --git a/port/cpl_vsil_curl.cpp b/port/cpl_vsil_curl.cpp
index 633b1636c707..b9677546a351 100644
--- a/port/cpl_vsil_curl.cpp
+++ b/port/cpl_vsil_curl.cpp
@@ -365,9 +365,6 @@ static std::string VSICurlGetURLFromFilename(
                 }
                 else if (EQUAL(pszKey, "empty_dir"))
                 {
-                    /* Undocumented. Used by PLScenes driver */
-                    /* This more or less emulates the behavior of
-                     * GDAL_DISABLE_READDIR_ON_OPEN=EMPTY_DIR */
                     if (pbEmptyDir)
                         *pbEmptyDir = CPLTestBool(pszValue);
                 }