I don't understand the behavior of that little fellow icon after the file name in the tab header.
Some times it's ≡, sometimes it's an "eject down" icon that looks like the one from the "follow file" button, sometimes this "eject down" icon is red.

However I haven't found any link with the actual "follow mode" of the file, or even as an indicator that there as been new lines added since I last viewed this tab..

I don't know if it's buggy or just an explanation is required.
BTW, the 'Wiki' link on top of this github repo doesn't seem to work.