I'm not confident in providing a publicly readable list of LDAP uids for security reasons
I get that. Would it be okay if I compile a list of uid->gitlab_account mappings for maintainers and include it in a project? Their uids are public in the DOAP files anyways.
On the foundation_id side, that's mainly the LDAP UID assigned to a specific username, not sure it's of much interest for the data gathering you're handling :-)
Some projects seem to like their data to GNOME accounts in this way