Highly, highly recommend hilock-mode for browsing code; hilock does ad-hoc syntax highlighting, so, as you read code and notice patterns, you write regexes for them and let Emacs spot them for you.

This turned out to be so useful for code reviews (we do a lot of those) that I "ported" it to a web app that lets us set hilocks that follow us from buffer to buffer (along with xrefs, class/method/fn definition sites, bookmarks, and a lot of other junk).