added comment

examples/js/loaders/FBXLoader.js

@@ -261,6 +261,7 @@
 
 		if ( typeof content === 'string' ) {
 
+			// ASCII format sometimes adds an extra character to the end of the content string
 			if ( content.slice( - 1 ) !== '=' ) {
 
 				content = content.slice( 0, - 1 );