[rainbowmverse]

>> I had more trouble finding this setting than I should have. Appears to be hamburger menu -> customize -> (bottom of page) density drop-down -> select compact. Still not sure if I like it. The tabs alone are still way too big for my liking.

Assuming it's the same as every Firefox since they started copying Chrome, the alt key should bring up the old-fashioned (and much more usable) menu bar.