Coc0 Not much to say, would highly appreciate the ability to change the user agent on Mobile as can be already done on the desktop version and most browsers on iOS.
Coc0 Vlad The best UI for this I can think of would be to add a section in the settings similar to iCab Mobile where one can choose from a common agents list, create and sort their own custom ones and separately also define what is used on a per website bases.
Vlad Hm if it is buried in the settings I do not think it would get much use. It needs to be accessible from thebrowsing sessions.
Vlad fjurz problem is that menu is already getting large (too large on smaller screens) so placing something as rarely used as this does not make sense.
ForumUser404 Vlad Not OP, but you could put the option under settings>search>user agent (right underneath search engine settings) Have a predefined list of agents and leave it at that to avoid complexity. No custom rules or anything.