wp-includes/load.php:663Sets the location of the language directory.
function wp_set_lang_dir() { if ( ! defined( 'WP_LANG_DIR' ) ) { if ( file_exists( WP_CONTENT_DIR . '/languages' ) && @is_dir( WP_CONTENT_DIR . '/languages' ) || ! @is_dir( ABSPATH . WPINC . '/languages' ) ) { /** * Server path of the language directory. * * No leading slash, no trailing slash, full path, not relative to ABSPATH * * @since 2.1.0 */ define( 'WP_LANG_DIR', WP_CONTENT_DIR . '/languages' ); if ( ! defined( 'LANGDIR' ) ) { // Old static relative path maintained for limited backward compatibility - won't work in some cases. define( 'LANGDIR', 'wp-content/languages' ); } } else { /** * Server path of the language directory. * * No leading slash, no trailing slash, full path, not relative to `ABSPATH`. * * @since 2.1.0 */ define( 'WP_LANG_DIR', ABSPATH . WPINC . '/languages' ); if ( ! defined( 'LANGDIR' ) ) { // Old relative path maintained for backward compatibility. define( 'LANGDIR', WPINC . '/languages' ); } } }}Introduced in 3.0.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/load.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.