The TextDecoder block was added in d681e0f08177659871afda2494e32075f35afc78, but it seems to have been commented out (for debugging purposes, maybe?) in the GLTFLoader.
@@ -666,7 +666,7 @@ THREE.GLTFLoader = ( function () {
if ( window.TextDecoder !== undefined ) {
- //return new TextDecoder().decode( array );
+ return new TextDecoder().decode( array );
}