So... here's the thing with #firefox
(Well, okay, one of many things.)
New tabs like to open at the end...
...unless they're from a link in Roundcube or Mastodon, which I have pinned at the top, in which case they appear near the top.
There used to be an extension called TabMixPlus which gave you control over this, and @Harena says that Vivaldi also does -- but as far as I can tell, neither Firefox nor the Tree Style Tab extension I use (despite all the control it does give you over how tabs are positioned relative to tab-trees) offers any.
I kind of feel like "user-controlled fork of Firefox" should be a top contender for major projects for Software Uprising to tackle, if we ever get enough funding to tackle some major projects.
(...which is never going to happen if I don't ever get around to setting up some basic infra for Software Uprising.)
@woozle Yeah, Vivaldi has it built in.
It's too bad Pale Moon never panned out, alas.
On the internet, everyone knows you're a cat — and that's totally okay.