(Often the ads on the websites.)
I am running Arch Linux here. When I boot my machine into a full desktop environment it uses 1.1 GB of memory total, for everything.
If I open Firefox, it in itself uses about 1.3 GB to have Firefox open with just HackerNews in 1 tab. I have no extensions except uBlock Origin.
I was pleasantly surprised at the tab unloading settings under "memory saver" in ungoogled-chromium.
"We have now approached the problem again by refining our low-memory detection and tab selection algorithm and narrowing the action to the case where we are sure we’re providing a user benefit: if the browser is about to crash."
I would prefer FF to be more proactive in unloading tabs way before "its about to crash" to keep system level memory pressure lower. Firefox is the main memory hog on my M1 mac.
Chrome can do this, there is no reason we should be stuck with "manual tab unload" and "unload when the browser is about to crash".
I am using an extension, but that just reinforces the argument: they could be doing much more here.
And as if Apple would ever block/pull/disapprove the world’s most popular browser.