Pretty sure that’s a mistake, they do elsewhere (https://transitapp.com/en/region/london/tfl ), and I’m using it ,right now.

Not doing so would be astonishing given how many people use public transport here, and that TFL’s data is really, really open + easy to use.

I checked twice in disbelief, but amongst many many places - London (UK) not being listed was surprising to me. I thought it's maybe some extra challenge of the oldest subway system.