Provide a contact form to contact users while keeping their e-mail address private
Problem to solve
Many users reasonably keep their e-mail addresses private. But this makes it problematic because it is then often hard to contact them. There are many legitimate reasons why one would like to contact them, for example, to report a security issue discovered in their code or sometimes even a deployment of their code they host on GitLab, when they have not provided alternative means of contact. Also, not always issues are enabled on their project.
Intended users
All GitLab users who need to contact another user directly.
Proposal
I would propose that signed-in users could use a contact form to contact another user, without exposing recipients e-mail address. My suggestion would be that this is an opt-out form, meaning that all users should get this contact form to their profile pages, but they could disable it if they really want through settings.
Permissions and Security
There is a potential of misuse by sending spam over this form. But this can be partially mitigated by preventing automatic contact form submissions through captcha.