FF has updated yesterday morning when I switched on my computer and went to FF.
Immediately when the FF-Information-Site with “Congratulations, you are running the newest version” (plus a QR-code to get FF for Android) popped up, I got a warning from Avast Free Antivirus.
I will add a screenshot of the warning. It’s in German but you will know the important parts anyway.
I had never before a warning from Avast when simply opening my FF-startpage.
I have the latest version of Firefox 98.0 and I can’t recall anything like that after the update.
That said the URL does seem somewhat strange, for it to be running a javascript .js file.
I ran a search on the domain - https://www.google.co.uk/search?q=certainalmostcontent.com - the first few are relevant.
I also tried to connect to the domain and got a strange result (see attached images) as this must have some redirect as it appears to try to redirect to moz-extension:// at which point my uBlock Origin extension blocks it.
I didn’t see anything like this when I updated to FF 98.0