"Project protected" and "locked" may sound like they restrict access in some way, but they don't really. All that means is that the profile can't be merged into another one (but other profiles can be merged into the PPP). In other words, it's the profile ID that is "locked". So other than changing the last name at birth, you can still edit any other part of the profile.
As for why a profile is project protected, we do that to profiles that are included in a project, both to protect the ID from merging into an incorrect name, and to let people know that a project is involved. If you're not sure which project, you could ask the Leader that protected the profile. Often the categories added will make it clear which project is involved, though.
Project protection is not a punishment! :) It's meant to increase collaboration, not take control away from profile managers. It means that major changes to the profile should be discussed amongst the project members. (And if you aren't a member of the project, you might want to be, since your family members are covered by it.)
