MasterPress 1.3.1 is a compatibility release for PHP 8 and WordPress 5.7. It still remains backwards compatible with older PHP versions.
MPFT_RelatedPostType :: count()
Return the count of post types selected in the UI. Since this overrides count the number of post types can also be retrieved by calling count directly on the field object.
Note: This method is intended for internal use and should not be called directly.