Gnosis Safe simu via Tenderly succeeds without signatures

Question

How is it possible that the Safe UI is able to simulate a call to execTransaction via Tenderly before collecting the signatures?

See this simulation, it succeeds even tho it only contains a single signature. It's a 2-of-4 setup, so it should fail with GS020 for not having enough signatures.

I thought Tenderly executes transactions against the real contracts, but seems like some of my assumptions are wrong about the way Tenderly and/or Gnosis Safe works.

Answer 1

With tenderly it is possible to overwrite the contract storage for a simulation and that's what the safe interface does: it overwrites the threshold in storage to 1 and uses a msg.sender signature from one of the owners.