Using WordPress ‘is_local_attachment()’ PHP function
Determines whether an attachment URI is local and really an attachment.
PHP
Using WordPress ‘is_404()’ PHP function
Determines whether the query has resulted in a 404 (returns no results).
Using WordPress ‘install_theme_search_form()’ PHP function
Learn how to use the WordPress 'install_theme_search_form()' PHP function to display a search form for searching themes in the WordPress theme directory
Using WordPress ‘install_themes_dashboard()’ PHP function
This article explains how to use the WordPress `install_themes_dashboard()` PHP function to display theme filters on various pages and interfaces