We're working on live public transport schedules as the first step to public transport routing. Here is the helper web app that shows currently supported GTFS feeds in different countries and cities and helps to match bus/tram/train stops from OpenStreetMap.org with stops from GTFS: https://gtfs-osm-matcher.organicmaps.app/
If you are interested in public transport schedules in your city, please let us know about feeds for your place/country, and help by adding/editing stops in OpenStreetMap.org

@organicmaps
Here's a GTFS data site for Okinawa, Japan. Seems to be both bus and ferry routes.

https://www.ottop.org/gtfs-opendata

And here's an API endpoint:

https://swagger.ottop.org/

Here's collected bus route data for many parts of Japan (Okinawa sourced from above I believe):

https://bus-routes.net/gtfs_list.php/

公共交通 | オープンデータ | 沖縄県 | 特定非営利活動法人OTTOP

GTFSフィード(GTFS-Schedule、GTFS-Realtime) 沖縄県内の公共交通機関の時刻表と地理的情報をGTFSとして配信

特定非営利活動法人 OTTOP
@jannem is it the official, original source feed? Or just an aggregate?

@organicmaps
It looks to me the top links is from an NPO that collects and promotes open data for Okinawa.

The bottom link is an aggregator that collect such data from all over the country.

Public transport is all run by private companies here, so there's probably no single "official" collection point for an area anywhere.