I bet they have a copy of every native library they use except like libc, and probably don't do any dead code elimination on those. And maybe they also have copies of the app for different ARM versions. And then an additional 20MB of JavaScript because everyone does these days.
Maps would be much more. Maybe some icons but the app is online only so most things could be loaded live. Its probably just god awful bloated js libraries.
I used a linux os for my phone for a while called SailfishOS and it was great having fully fledged apps for things like maps, music, etc in the kB range. The app i used for public transport schedules was 15kB.