What does -H+ mean in a chemistry mechanism

-H+ Negative goes with positive, so we end up with a neutral atom of hydrogen :flushed_face::flushed_face: /s

It means loses a proton. Deprotonation.

Edit: I didn’t notice the upper equation at first because Bad eyes, but as shown, the H2SO4 would be understood to have protonated the CrO3. When the alcohol reacts through O at the Cr atom, generating an intermediate species with a protonated ether, any of HSO4-, H2O or CrO3 could act as base to remove that proton.

H:- is hydride, H+ is proton

as the others have said, it is a shortcut that indicates a proton (H+) has been abstracted by a base or lone pair elsewhere in the reaction, without having to draw this out. common in reaction mechanisms with a lot of protons being shuttled around, like anything to do with carbonyls/acetals or oxo-metals.

I wonder how most inorganic chemists feel with that Chromium(IV) oxide hydroxide thing.

It might help if you shared what exactly is confusing you about them, or are you just not sure what they refer to?

Unrelated, but what does everyone think of that intramolecular proton transfer?

A picture would be better. However I assume it is meant to either describe deprotonation or to describe the 'killing' of (excess) protic species (e.g. via destillation, perception, ...) so that the pH decreases.