WowAce

Unit config -> Player -> Bars -> Class/misc bars.

Enable XP/Rep bar: checked.

It's supposed to automatically hide when at the level cap or no rep is tracked. I'm at max lvl and don't track any factions atm, but the bar is still there (empty). Unchecking hides the bar.

Enable <class> mana bar: checked.

Not sure about this one, but I read the tooltip as in "adds the new mana bar ONLY WHEN in Bear or Cat Form". Is active outside any forms, too. Unchecking hides the bar.

And in addition to the always-active-reputation/XP-bar, there appeared another bar which I couldn't find the option for to hide yet. No idea what it does or why it's there, but it messes with the player picture. I added screenshots to how it was before the pre-patch (only HP/mana bar) and how it is now (without actively changing anything in the settings since pre-patch). https://imgur.com/a/xjv1w4L