wp-includes/class-wp-customize-manager.php:2321Filters the active theme and return the name of the previewed theme.
$current_thememixedstring public function current_theme( $current_theme ) { return $this->theme()->display( 'Name' ); }Introduced in 3.4.0. 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.