It's probably a static feed, and they've probably had to do some lifting to define the layout and map that to the raw data they get from Network Rail, and they've probably not updated it for newly opened stations. There is a station near me that's been open for many years that isn't shown there either.

There are many different alphabet-soup coding systems used across Network Rail, retailing systems, and the wider railway industry to identify locations on the network. Station names will often be different in different databases; look at any station with an apostrophe in and you'll find it inconsistently named in different places.

Yeah it only seems to show small station near me, and not the main city stations, not sure why but it's very incomplete, and not related to age. For example Sheffield station isn't on the map, and that opened in 1870.