diff --git a/src/cmark.h b/src/cmark.h
@@ -552,6 +552,12 @@ char *cmark_render_latex(cmark_node *root, int options, int width);
*/
#define CMARK_OPT_HARDBREAKS (1 << 2)
+/** `CMARK_OPT_SAFE` is defined here for API compatibility,
+ but it no longer has any effect. "Safe" mode is now the default:
+ set `CMARK_OPT_UNSAFE` to disable it.
+ */
+#define CMARK_OPT_SAFE (1 << 3)
+
/** Render raw HTML and unsafe links (`javascript:`, `vbscript:`,
* `file:`, and `data:`, except for `image/png`, `image/gif`,
* `image/jpeg`, or `image/webp` mime types). By default,