That is easy.
Go to the homepage of the game, search for any telemetry output info. This is called API or a section for programmers.
You may also ask in the forum of the game where this telemetry output info is available. Maybe you get this if you ask the game support hotline.
After you found this page, you post the link here. That is enough to build a plugin.
For example of LFS:
https://en.lfsmanual.net/wiki/OutSim_/_OutGaugeYou find some words like gauges, speed, roll, accel, pitch, orientation ...
If a answer is correct or did help you for a solution, please use the solve button.