wp-includes/class-wp-textdomain-registry.php:155Sets the custom path to the plugin's/theme's languages directory.
$domainstring$pathstring public function set_custom_path( $domain, $path ) { // If just-in-time loading was triggered before, reset the entry so it can be tried again. if ( isset( $this->all[ $domain ] ) ) { $this->all[ $domain ] = array_filter( $this->all[ $domain ] ); } if ( empty( $this->current[ $domain ] ) ) { unset( $this->current[ $domain ] ); } $this->custom_paths[ $domain ] = rtrim( $path, '/' ); }Introduced in 6.1.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-textdomain-registry.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.