I’m having trouble finding older revisions of the HTML5 specification. I keep finding resources such as WHATWG’s version, or HTML5 differences from HTML4 and my google-fu is failing me.
Is there a repo where I can browse different versions of the HTML5 spec, and (more importantly) compare different versions?
It depends on how far back you want to go, but for looking at earlier versions a couple of options spring to mind.
The latest version of the spec has a list of links to some previous drafts at the very start.
The other option is the Wayback Machine, but it seems it stopped indexing the pages mid-2011.
Don’t know how you’d go about comparing them though. You might be better looking at the diff tracker although that’s tracking changes on the WHATWG version.