where do I find all lua functions?

I see a lot of beamng apps that use functions like "extensions.beamRegeneration.regenerate()" that I cat find anywhere in beamng (C:\Program Files (x86)\Steam\steamapps\common\BeamNG.drive\lua\vehicle) or on the internet....

 

I know I can find it in there but where did he find all these functions? because it feels like there are wayyy more functions than I can find in beamng. btw, I'm making an app so is important. I am trying to find how I can fix my tires when they are deflated..

 

oh well, that's unfortunate.. I've also been searching through all files in beamng with notepad, couldn't find anything to inflate the tires..