key3.db is an NSS certificate database.
This is a key database in the legacy database format. Consider migrating to cert9.db and key4.db which which are the new sqlite-based shared database format with support for concurrent access.
cert9.db(5), key4.db(5), pkcs11.txt(5),
The nss libraries were written and maintained by developers with Netscape, Red Hat, Sun, Oracle, Mozilla, and Google.
Authors: Elio Maldonado <firstname.lastname@example.org>.
Licensed under the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.