I’d assumed that this forum was dormant until I discovered the new address by chance. My first reactions are
- Why can’t I use my usual browser, Pale Moon?
- Why do I have to use a longer password? — this isn’t a financial site!
- How do I log out?
- As for Pale Moon: I can’t help you there.
- Longer (and more complicated) passwords are becoming the norm for security.
- Just close the window.
Ok, so the longer password thing is just standard for the new Forum software. It’s not a financial site, but at the same time you don’t really want someone logging into your account and publishing something under your name, that you might want … 
(as Keith says, it’s just the new default, not something we’ve specifically added or enforced)
Closing the browser will close your session, there is an explicit logout if you need it … click on your avatar in the far top right (looks like a green “D” for you), select the very bottom option which is a little person / chess pawn icon, then click “Logout”.
(Why does Pale Moon not work? I’ve not tried it, but if it’s a fork of the Mozilla code … Firefox seems to work Ok?)