libnssdbm is deprecated upstream (see https://bugzilla.mozilla.org/show_bug.cgi?id=1360778#c8 ), and upstream recommends using the default sqlite backend instead. The backend has known issues. According to that link, Firefox itself doesn't use or build it anymore. We should consider following suit, and making sure nothing in the distro is using it. (*If* something still is, we should move it to a deprecated legacy package.) - Josh Triplett