Bars Next to Favicon: Purpose?

[LPDev]

Good morning!

Just a quick question this time around from someone who just upgraded to 4.x last week.  Every now and again, we see double bars in our browser tab (attached below) next to the favicon on our forum directory. If someone could let me know what those are for, I'd greatly appreciate it.  I'm guessing it has something to do with there being new topics or posts since we last looked at that browser tab, but I'd like to know for sure.

Thanks!

 

[Navigare]

I think it's supposed to be a "Pause" sign, meaning that the page isn't actively updating in the background.