Add a first line in the file “https://github.com/getkirby/demokit/blob/master/site/plugins/blog/snippets/header.php”:
<!DOCTYPE html>
It is missing for a standard compliant html.
Remarks:
- This file is not used in the demo kit because its use is overridden. But it is possible that a user uses this plugin in his own project and uses this header file.
- Furthermore, in my opinion, error-free code is always desirable.