In OPAC user account, the borrower attributes are not visible anymore. There where visible in opac-userdetails.pl that as been replaced by opac-memberentry.pl.
Fridolin, On the patron attributes types form (admin/patron-attr-types.pl), you can check the "Display in OPAC" checkbox to see the attribute displayed on opac-memberentry.pl page. Does not it what you are searching for?
Frido confirmed me that it's not a bug.
I found the correction in Bug 12718 *** This bug has been marked as a duplicate of bug 12718 ***