Learn English – When do we use “would have had”

auxiliary-verbsmodal-verbstense

Source

In addition, users with this privilege level can also begin reviewing suggested edits (which previously you would have had to suggest). These edits remain in a pending state until they get enough votes to either approve them and make the edits take effect or reject them and discard the edit. Two votes in either direction will finalize the action, except on Stack Overflow where three votes are required.

I have heard have had and had had before but encountered would have had for the first time. I think had could have done a good job in the sentence. Can you explain the meaning of the bold part in the passage?

Also, "would have" is which kind of a phrase?

Best Answer

"Would have" expresses some uncertainty. The help text needs to explain things both to users who suggested many edits before they reached that privilege level and to users who didn't suggest any, so instead of implying that the user definitely did have to suggest edits, it just says that, if the user did try to make an edit in the past, that edit had to be a suggested edit.

In other words, it links something that's possible with something else that's definitely required if the first actually happens.