I got these messages trying to user The Events Calendar with the Fizzie theme.
Deprecated: Theme without header.php is deprecated since version 3.0.0 with no alternative available. Please include a header.php template in your theme. in C:\apache\htdocs\wordpress\wp-includes\functions.php on line 4973
Deprecated: Theme without footer.php is deprecated since version 3.0.0 with no alternative available. Please include a footer.php template in your theme. in C:\apache\htdocs\wordpress\wp-includes\functions.php on line 4973
This no longer happens. Gutenberg/core was updated a while ago.
Tested anyway, with WordPress 6.2-beta5 and The Events Calendar v6.0.10 on s.b/cwiccer with Fizzie v1.2.0
I got these messages trying to user The Events Calendar with the Fizzie theme.
Deprecated: Theme without header.php is deprecated since version 3.0.0 with no alternative available. Please include a header.php template in your theme. in C:\apache\htdocs\wordpress\wp-includes\functions.php on line 4973
Deprecated: Theme without footer.php is deprecated since version 3.0.0 with no alternative available. Please include a footer.php template in your theme. in C:\apache\htdocs\wordpress\wp-includes\functions.php on line 4973