Registers widget control callback for customizing options.

Validates and remaps any “orphaned” widgets to wp_inactive_widgets sidebar, and saves the widget settings. This has to run at…

Sanitizes an HTML classname to ensure it only contains valid characters.

Performs esc_url() for database or redirect usage.

Saves the XML document into a file.

Returns the screen layout options.

Returns the screen’s per-page options.

Determines the concatenation and compression settings for scripts and styles.

Saves option for number of rows when listing posts, pages, comments, etc.

Sets/updates the value of a transient.