Email has become somewhat unfashionable as a collaboration tool for open-source projects, but there are still a number of projects—such as PostgreSQL and the Linux kernel—that expect contributors to send and review patches via email. The aerc mail client is aimed at developers looking for a text-based, efficient, and extensible client that is meant to be used for working with Git and email. It uses Vim-style keybindings by default, and has an interface inspired by tmux that lets users manage multiple accounts, mails, and embedded terminals at once.
By terminal-based email client standards, aerc is relatively new. The popular Mutt text-based email client was first released in 1995, and its fork NeoMutt was first released in 2016. The venerable Pine mail client was first released in 1992, and its rewrite Alpine appeared in 2007. At only six years old, aerc is a new kid on the block. Drew DeVault made the first commit to the aerc project in January 2018, and announced the 0.1.0 pre-release in June 2019. The project is written in Go, and made available under the MIT License.
The name was something of a mystery, so I emailed DeVault to ask where it came from. He replied that it originally stood for "asynchronous email reading client", to signify that the user interface and the network code to communicate with IMAP servers, etc., were decoupled to make the user experience better. That name, he said, was not very meaningful and "soon fell into the dustbin of history".