This proposal aims to enable pre-checking for runtime upgrade on parachains: With pre-checking enabled a parachain is only allowed to upgrade their runtime after validators have tried compiling it and they agree it is good, as opposed to just accepting it blindly and then fail when the parachain tries to produce blocks with the new runtime. This is just generally a good idea, exists for a while already and has been successfully tested on Versi, Rococo and Westend. It is also required for rolling out slashing as it helps reducing the risk of unjustified slashes.
Parachains need to support the go_ahead_signal, but that should be a non issue as this has been introduced over a year ago.
Preimage is submitted. Make sure to review and vote at your convenience!