Excellent solution to deal with seriously buggy/bloated Yahoo email "classic mail" webpage (recent forced "upgrade" from yahoo) and also google's forced removal of lightweight sending text messages from browser (replacement is bloated, extremely slow). IN BOTH CASES - set user-agent to android/firefox browser for *.yahoo.com or voice.google.com as appropriate, and now I get a usable, lightweight presentation without yahoo's bugs/bloat and google's bloat of their desktop browser presentations. Also user-agent changer adds no perceptible load to my extremely low-resource computer, excellent!