postbox

Install command: 
brew install --cask postbox

Name: Postbox

Email client focusing on privacy protection

https://www.postbox-inc.com/

/api/cask/postbox.json (JSON API)

Cask code on GitHub

Current version: 7.0.64

Requires: macOS >= 10.13

postbox is built for Intel macOS and so requires Rosetta 2 to be installed.
You can install Rosetta 2 with:
    softwareupdate --install-rosetta --agree-to-license
Note that it is very difficult to remove Rosetta 2 once it is installed.

Analytics:

Installs (30 days)
postbox 16
Installs (90 days)
postbox 69
Installs (365 days)
postbox 340
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