Post-quali scrutineering

When a team builds/designs a car, do they hand over the “blueprints” to the FIA so they know what to look for if cheats are applied afterwards?

For example, with Ferrari’s new spec 3 engine performance suspicions, is it up to the FIA to find out if they are cheating? A catch me if you can scenario?

Edit: I’m not saying they are cheating, or even breaking the rules, just curious as to when new tech is introduced how is it verified or what the process is in general.