Hey there, I and my colleagues who use Linux have all started seeing massive performance decrease & tabs frequently reporting "a web page is slowing down your browser" issues starting around August 5 or 6 of this year. I started a complaint thread in my company slack about this on August 6, and unrelated to that, someone else started a similar thread on august 18. At first I thought it was just me, or just some quirk of my linux distribution, or a pattern of using the software. But I actually switched Linux distros from Ubuntu to Arch to see if it would help (it didn't) and now that I've seen the behavior consistently across a whole bunch of different apps, I think it's a bug. It seems to affect heavier webapps like Quip and Slack, much more so than lighter webpages. Again, nothing was wrong before August of this year and now, depending on how I use my computer, I frequently get "a web page is slowing down your browser", cpus pegged to 100%, which ends up with me closing tabs/ sometimes restarting firefox multiple times per day. Nobody on Chrome is complaining about similar issues. I did run the profiler for a bit while such an issue was going on, and am happy to share it, although it has slightly-private information from one of our company slacks and I don't know if this forum is public.