Yep, the browser has the UCD info built into it (a simplification... but basically). Similarly our mobile devices and various backend languages have the same da

Yep, the browser has the UCD info built into it (a simplification... but basically). Similarly our mobile devices and various backend languages have the same data backed into it. This is where there are sometimes discrepancies between how a given browser or device would output this data, as it could be working off of an outdated version of Unicode's data. Some devices even overwrite the default Unicode behavior. There are just SO many languages and SO many regions and SO many combinations thereof that even Unicode can't cover all the bases. It's all very fascinating from an engineering perspective.