How do I open Firefox (my default browser) with a search for [[selection] on macOS? The url schemes from iOS for iCabMobile obviously don’t work…
How to open Firefox/my default browser with a search on macOS?
On the Mac, if Firefox is your default browser, you should not need to do anything special. A search action which uses http URLs (like the Google example)should just open in Firefox like any other link would.
Of course! I can just open a url with the search on google! 
That’s certainly good enough. However is there a way to tell Firefox on macOS to add the selection to the search field and initiate a search in Firefox’s default search engine?
On iOS iCabMobile has an x-icabmobile/search url scheme for this…
I have no idea. I’ve never run across any documentation of what, if any, custom URL schemes Firefox implements for things like this and if they are supported on both iOS and Mac.