apply_filters( 'postmeta_form_keys', array|null $keys, WP_Post $post )

Filters values for the meta key dropdown in the Custom Fields meta box.

Description

Returning a non-null value will effectively short-circuit and avoid a potentially expensive query against postmeta.

$keys: Pre-defined meta keys to be used in place of a postmeta query. Default null.
$post: The current post object.

Used By
Used By	Description
wp-admin/includes/template.php: meta_form()	Prints the form in the Custom Fields meta box.

Changelog
Version	Description
WP-4.4.0	Introduced.