_canonical_charset() – Retrieve a canonical form of the provided charset appropriate for passing to PHP functions such as htmlspecialchars() and charset html attributes.
_clear_modified_cache_on_transition_comment_status() – Clear the lastcommentmodified cached value when a comment status is changed.
_close_comments_for_old_post() – Close comments on an old post. Hooked to comments_open and pings_open.
_close_comments_for_old_posts() – Close comments on old posts on the fly, without any extra DB queries. Hooked to the_posts.
_copy_dir() – Copies a directory from one location to another via the WordPress Filesystem Abstraction.
_custom_header_background_just_in_time() – Registers the internal custom header and background routines.
_custom_logo_header_styles() – Adds CSS to hide header text for custom logo, based on Customizer setting.
_excerpt_render_inner_columns_blocks() – Render inner blocks from the `core/columns` block for generating an excerpt.
_get_custom_object_labels() – Build an object with custom-something object (post type, taxonomy) labels out of a custom-something object
_prime_comment_caches() – Adds any comments from the given IDs to the cache that do not already exist in cache.
_prime_network_caches() – Adds any networks from the given IDs to the cache that do not already exist in cache.
_prime_post_caches() – Adds any posts from the given IDs to the cache that do not already exist in cache
_prime_site_caches() – Adds any sites from the given IDs to the cache that do not already exist in cache.
_prime_term_caches() – Adds any terms from the given IDs to the cache that do not already exist in cache.
_update_posts_count_on_delete() – Handler for updating the current site’s posts count when a post is deleted.
_update_posts_count_on_transition_post_status() – Handler for updating the current site’s posts count when a post status changes.
_update_term_count_on_transition_post_status() – Update the custom taxonomies’ term counts when a post’s status is changed.
_wp_ajax_delete_comment_response() – Sends back current comment total and new page links if they need to be updated.
_wp_check_existing_file_names() – Helper function to check if a file name could match an existing image sub-size file name.
_wp_check_for_scheduled_split_terms() – In order to avoid the _wp_batch_split_terms() job being accidentally removed, check that it’s still scheduled while we haven’t finished splitting terms.
_wp_check_for_scheduled_update_comment_type() – In order to avoid the _wp_batch_update_comment_type() job being accidentally removed, check that it’s still scheduled while we haven’t finished updating comment types.
_wp_check_split_default_terms() – Check default categories when a term gets split to see if any of them need to be updated.
_wp_check_split_terms_in_menus() – Check menu items when a term gets split to see if any of them need to be updated.
_wp_customize_changeset_filter_insert_post_data() – Filters changeset post data upon insert to ensure post_name is intact.
_wp_delete_customize_changeset_dependent_auto_drafts() – Delete auto-draft posts associated with the supplied changeset.
_wp_keep_alive_customize_changeset_dependent_auto_drafts() – Make sure that auto-draft posts get their post_date bumped or status changed to draft to prevent premature garbage-collection.
_wp_menu_item_classes_by_context() – Adds the class property classes for the current context, if applicable.
_wp_personal_data_cleanup_requests() – Cleans up failed and expired requests before displaying the list table.
_wp_post_thumbnail_class_filter_add() – Adds ‘_wp_post_thumbnail_class_filter’ callback to the ‘wp_get_attachment_image_attributes’ filter hook. Internal use only.
_wp_post_thumbnail_class_filter_remove() – Removes the ‘_wp_post_thumbnail_class_filter’ callback from the ‘wp_get_attachment_image_attributes’ filter hook. Internal use only.
_wp_post_thumbnail_class_filter() – Adds a ‘wp-post-image’ class to post thumbnails. Internal use only.
_wp_privacy_completed_request() – Marks a request as completed by the admin and logs the current timestamp.