There is no development done yet. We currently discuss what the best mechanism would be. We host a session at the barcamp next week.
At the moment there are multiple options proposed in the discussion you linked.
- A mechanism in Cumulus that enables parachains to recover without external help.
- A mechanism on the Relay Chain that allows parachains to delegate recovery powers to an entity. (suggested by Bryan Chen)
Both options have their pros and cons. Option 1 might not solve all the errors that could occur, while option 2 is difficult to implement in a decentralized fashion (the token holders on the bricked parachain should be able to vote).
An interesting discussion point regarding option 2 is also how much power should be moved to the relay chain. The code of the parachain defines the rules that must be followed on this chain. If we now move parts of this to the relay chain, the parachain gives up a portion of its sovereignty and it also becomes more complicated to reason about the rules on a parachain. You would need to take the parts into account that now live on the relaychain.
Another issue is also, that a stalled parachain might even be the luckiest error case. A security vulnerability that let’s you mint tokens could be even worse. Rollbacks might not be possible in these cases since the tokens could already be moved to other chains via XCM.