I talked to the Docs team and it looks like that doc won’t be resurrected, mostly because it had a lot of out-of-date info. They are looking to add some new relevant documentation though, in the new year.
In the mean time, the lovely Andrea sent me this. Apologies if it doesn’t help.
If they want an object they import to be destructible they can check the Can Be Damaged option in the Details panel when they select their asset in the viewport.
