https://github.com/jenkinsci/jenkins/blob/2776f4dc77d12650e310dc10c005f95937ac3469/core/src/main/resources/hudson/AboutJenkins/index.jelly#L51-L52 records some components we include that aren't coming from Maven.
I'm fairly sure at least Material Icons are missing here, and probably doesn't hurt to mention Tango and RRZE too.
FYI fqueiruga timja you're probably best informed what we use for the UI here.