The Tavern

Is the quality of Gozag's shops influenced by depth? If yes, how does the game calculate that? If I'm e.g. in Elf:1, is that counted as deeper than Lair:3 or D:15?

No. Learndb says the quality of the shop contents is based on your XL.

it used to be like that in what, 0.17? Ahh, dipping Depths for opening shops...