This shouldn't require access to all websites to change my user agent on a single site.

Make it even worse. I can't believe this useless thing has such high rating.

Edit: This used to work extremely well but as of recently as others are saying it no longer works right and causes the entire browser to freeze up. I will happily return to five stars once this is fixed!
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Thank you this is brilliant!!

Thought I was in the add on manager.

needs to be updated for latest firefox android update.