wp-includes/revision.php:920Filters terms lookup to set the post format.
$termsarray$post_idint$taxonomystringarrayfunction _wp_preview_terms_filter( $terms, $post_id, $taxonomy ) { $post = get_post(); if ( ! $post ) { return $terms; } if ( empty( $_REQUEST['post_format'] ) || $post->ID !== $post_id || 'post_format' !== $taxonomy || 'revision' === $post->post_type ) { return $terms; } if ( 'standard' === $_REQUEST['post_format'] ) { $terms = array(); } else { $term = get_term_by( 'slug', 'post-format-' . sanitize_key( $_REQUEST['post_format'] ), 'post_format' ); if ( $term ) { $terms = array( $term ); // Can only have one post format. } } return $terms;}Introduced in 3.6.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/revision.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.