wp-includes/class-wp-customize-manager.php:1073Dismisses all of the current user's auto-drafts (other than the present one).
int protected function dismiss_user_auto_draft_changesets() { $changeset_autodraft_posts = $this->get_changeset_posts( array( 'post_status' => 'auto-draft', 'exclude_restore_dismissed' => true, 'posts_per_page' => -1, ) ); $dismissed = 0; foreach ( $changeset_autodraft_posts as $autosave_autodraft_post ) { if ( $autosave_autodraft_post->ID === $this->changeset_post_id() ) { continue; } if ( update_post_meta( $autosave_autodraft_post->ID, '_customize_restore_dismissed', true ) ) { ++$dismissed; } } return $dismissed; }Introduced in 4.9.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-customize-manager.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.