What is Thunderbird?
Thunderbird is one of the most widely used open-source email clients in the world. Mozilla originally developed the software in 2004, but the project waned in 2014/15, and Mozilla stated that they would only deliver security and maintenance updates in the future. Until recently, the community maintained the software when a Mozilla Foundation subsidiary, MZLA Technologies Corporation, took over. Today, the improvements in security and stability are very much appreciated, and since version 78, Thunderbird has built-in OpenPGP encryption technology enabled by default. Earlier versions used the available PGP technology, but it needed to be installed as a supplemental plugin.