Hello, I cannot add a new search engine to '''Firefox Developper Edition'''. When I want to add a new search engine with [https://ready.to/search/en/ Ready2Search] I get an error message: ''Submitted information of your web browser is Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Firefox/78.0. Your use Macintosh and Firefox. However, your Firefox isn't updated. If you'd like to install OpenSearch plug-in to Firefox, you need to update Firefox.'' Same trying to add a new search engine with [https://mycroftproject.com/google-search-plugins.html Mycroft Project] doesn't work. I have the latest update of Firefox Developper Edition (78.0b9 (64 bits) Mac). How to do this, please help ? Thank you.