Web Extension equivalents to legacy Firefox add-ons
docs.google.com
docs.google.com
I did lose a few hours over XMarks' inability to sync Firefox search keywords correctly anymore (it's not solved, but you can input the keywords yourself on all your machines and they won't be erased) but that's it.
Firefox 1.0 arguably had better UI, or at least the option to make it better.
Also, I remember running it on a 32MB machine. Today, with only this single HN tab open, memory consumption is reported at somewhere above half a gigabyte.
On the other hand, I will trade memory use for many things. One thing that is infuriating to me is that despite the memory hog, a single tab can still crash the whole browser. All the memory use doesn't even buy you failure isolation.
I really, truly, hate inputting anything more than a couple of lines in to websites. Worse when you're fighting WYSIWYG editors, fixed box widths. Even worse than that is when you spend 20 minutes filling in the box, hit submit and find your session timed out.
"It's All Text" allowed me to just click an "edit" button beside the text box, go edit the thing in my favourite text editor, hit save and then go click submit in the browser. If the site screwed up somehow, the text was still open in my text editor.
I miss it, too. But not enough to reimplement it, at least not yet.
So, in Firefox, if you open enough tabs, it will eventually overflow them and then you can scroll the tab list either with those little scroll buttons to the left and right or with the scrollwheel.