WP_Translation_Controller::load_file( string $translation_file, string $textdomain = 'default', string $locale = null ): bool

101	public function load_file( string $translation_file, string $textdomain = 'default', ?string $locale = null ): bool {102		if ( null === $locale ) {103			$locale = $this->current_locale;104		}105 106		$translation_file = realpath( $translation_file );107 108		if ( false === $translation_file ) {109			return false;110		}111 112		if (113			isset( $this->loaded_files[ $translation_file ][ $locale ][ $textdomain ] ) &&114			false !== $this->loaded_files[ $translation_file ][ $locale ][ $textdomain ]115		) {116			return null === $this->loaded_files[ $translation_file ][ $locale ][ $textdomain ]->error();117		}118 119		if (120			isset( $this->loaded_files[ $translation_file ][ $locale ] ) &&121			array() !== $this->loaded_files[ $translation_file ][ $locale ]122		) {123			$moe = reset( $this->loaded_files[ $translation_file ][ $locale ] );124		} else {125			$moe = WP_Translation_File::create( $translation_file );126			if ( false === $moe || null !== $moe->error() ) {127				$moe = false;128			}129		}130 131		$this->loaded_files[ $translation_file ][ $locale ][ $textdomain ] = $moe;132 133		if ( ! $moe instanceof WP_Translation_File ) {134			return false;135		}136 137		if ( ! isset( $this->loaded_translations[ $locale ][ $textdomain ] ) ) {138			$this->loaded_translations[ $locale ][ $textdomain ] = array();139		}140 141		$this->loaded_translations[ $locale ][ $textdomain ][] = $moe;142 143		return true;144	}