Transport Changes

how google gets information about changes in transport? I am a novice programmer and I am currently developing a passenger information system, namely a port to a computer in the form of a program, and I am currently working with a table where stops are entered, but when changes are made, a running line appears below (under the stops) with these changes. Adding a running line is not a problem for me, but I need to somehow get data about these changes, after viewing sites, on 3 of them it shows exactly 1 to 1 information, I also found the same thing in Google, it remains to understand how it got this information (with what script, so that I could shove this information into my program).  

Op 7/7/24 om 12:35 schreef Michał Postemskii:
Transit agencies provide scheduled information in GTFS to Google. And
likely NeTEx towards European National Access Points. Google receives
GTFS-RT for day-to-day changes, SIRI Estimated Timetables would be the
European equivalent.

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Stefan