In a race between you supporting chrome and firefox supporting chrome casting you have won!
I guess moving on to this new incarnation made it easier to port the code for use as a chrome extension.
For those wanting to make the browser switch here is url to chrome beta extension
…writing this post from chrome…logged in via github using Chrome Kee extension…sweet!
Hate to say goodby to firefox and use yet another google hegemony product but mozilla did have years to come up with chromecast addon. Too lately firefox from 55+ is broken on arm ubuntu.