According to our Data Removal Policy document (https://musicbrainz.org/doc/Data_Removal_Policy) we remove birth dates on request. This is true, but they do remain in the edit history. We should also scrub them from there, without otherwise damaging the edit data. Ideally, the change would lead to the data showing [REDACTED] (or the like) instead of the birth date, but leave everything else the same.