How to lookup UUIDs for default reviewers via the API (which is possible via the UI)

[Deleted user]

Hello,

I've got a security model where (most) users are not granted admin privileges for repositories but need to be able to add (not modify / delete) default reviewers. This is usually required when they are creating new repositories, I need to enforce certain repository settings (merge checks, no public forks etc) when repositories are being created so I have some automation utilising the API for this.

Since about a month ago it is no longer possible to add default reviewers by username and UUIDs need to be used. I do not see any way of looking up user UUIDs via the API based on their name / e-mail - it is possible to look up users via the UI though (both in the default reviewers settings which requires higher privileges and the PR pages themselves which don't require higher privileges), from what I've noticed the UI uses `mention_id`s for this.

How can I make it possible for my users to add default reviewers? Even as an admin, even in the UI, I can't see a way of fetching every team members' UUID to make a map / catalogue which could be used for this...