What is the User role in the Organization for?

I was hoping the User would not be able to start a cloudbuild, but would still be able to look at builds and get share links. But when I set a collaborator to User, they can still start builds and in fact there doesn’t appear to be much of a difference between Users and Managers.

Can anyone clarify the roles? And might there be a role which limits a collaborator’s abilities to just viewing?

The roles are intended to work the way you describe above, however we are still building out proper support for all of those across the services. Currently there is not a way to limit someone to just viewing in Cloud Build, although it’s something we hope to get to fairly soon.