Vimeo Player Parameters

I am embedding some Vimeo video content on a site and clicking the "share" link gets me an iframe with src url like this:

https://player.vimeo.com/video/295476812?h=3b476d8fcb&color=f7021f

After reading the docs for player parameters overview I see quite a few options there but nothing that outlines what the h=3b476d8fcb parameter is for.

What does the h= parameter do?