When ever I was in the situation of taking something over being left alone with doc's and comments about the working code and no one to hit up I would have loved to find opinion based hints. But all I usually find is:

//TODO!!!!

So I'd say, document it as technically and accurate as you can, but before leaving out an important information, your replacement will forgive you being opinion based instead of just writing another "I didn't finish this"-comment aka /*TODO!!!!*/.

Well, at least I would.

When ever I was in the situation of taking something over being left alone with doc's and comments about the production-code and had no one to hit up,

I would have loved to find opinion based hints. But all I usually find is:

//TODO!!!!

So I'd say, document it as technically and accurate as you can, but before leaving out an important information, your replacement will forgive you being opinion based instead of just writing another "I didn't finish this"-comment aka /*TODO!!!!*/.

Well, at least I would.