diff --git a/reference/filesystem/functions/is-executable.xml b/reference/filesystem/functions/is-executable.xml
index 75c6518567..8eda8f9b23 100644
--- a/reference/filesystem/functions/is-executable.xml
+++ b/reference/filesystem/functions/is-executable.xml
@@ -37,7 +37,8 @@
   &reftitle.returnvalues;
   <para>
    Returns &true; if the filename exists and is executable, or &false; on
-   error.
+   error. On POSIX systems, a file is executable if the executable bit of the
+   file permissions is set. For Windows, see the note below.
   </para>
  </refsect1>
 
@@ -74,6 +75,17 @@ if (is_executable($file)) {
   &reftitle.notes;
   &note.clearstatcache;
   &tip.fopen-wrapper.stat;
+  <note>
+   <simpara>
+    On Windows, a file is considered executable, if it is a properly executable
+    file as reported by the Win API <literal>GetBinaryType()</literal>; for BC
+    reasons, files with a <filename>.bat</filename> or <filename>.cmd</filename>
+    extension are also considered executable. Prior to PHP 7.4.0, any non-empty
+    file with a <filename>.exe</filename> or <filename>.com</filename> extension
+    was considered executable. Note that <envar>PATHEXT</envar> is irrelevant
+    for <function>is_executable</function>.
+   </simpara>
+  </note>
  </refsect1>
 
  <refsect1 role="seealso">