"connecting to cloffext.com" a concern?

[Circlotron]

Just tonight I noticed on Firefox when I go to Google, down the bottom where it shows you all the various servers you are being connected to, it also says "connecting to cloffext.com". Some sites list it as a Windows malware thing. I put a line in my hosts file to block it, so is it something to be concerned about on my Linux system? Mint Mate 18.3

[Circlotron]

While looking it up, other people were having this trouble and also with "connecting to fileserver.xyz"' I removed Best YouTube Downloader and it doesn't seem to be happening now. Wait and see what happens.