A website requires google account to log in. disallowed_useragent 403

You need to modify the webviewer useragent by removing ; wv from it.

There are a variety of extensions available to do this. Oddly I am just in the middle of working on a new one.

You can try CustomWebView or WebViewTools

search here:

Extension Links

Taifun
Puravidaapps

Lost Extensions 1
Inactive Communities

Lost Extensions 2
Thunkable/Others