_clear_modified_cache_on_transition_comment_status() – Clear the lastcommentmodified cached value when a comment status is changed.
_delete_attachment_theme_mod() – Checks an attachment being deleted to see if it’s a header or background image.
_get_plugin_data_markup_translate() – Sanitizes plugin data, optionally adds markup, optionally translates.
_wp_delete_tax_menu_item() – Serves as a callback for handling a menu item when its original object is deleted.
_WP_Editors::wp_mce_translation() – Translates the default TinyMCE strings and returns them as JSON encoded object ready to be loaded with tinymce.addI18n(), or as JS snippet that should run after tinymce.js is loaded.
_wp_expand_nav_menu_post_data() – If a JSON blob of navigation menu data is in POST data, expand it and inject it into `$_POST` to avoid PHP `max_input_vars` limitations. See #14134.
_wp_image_meta_replace_original() – Updates the attached file and image meta data when the original image was edited.
_wp_menu_item_classes_by_context() – Adds the class property classes for the current context, if applicable.
_wp_mysql_week() – Return a MySQL expression for selecting the week number based on the start_of_week option.
_wp_scripts_maybe_doing_it_wrong() – Helper function to output a _doing_it_wrong message when applicable.