FossaMail is a Thunderbird-based mail/news client building on the Pale Moon web browser core.
The source tree is mostly laid out like the Mozilla Thunderbird tree and links to Pale Moon as a git sub-repo for easy management and updates of the back-end code.
FossaMail is currently a discontinued product. If you want to pick up the torch, feel free to fork this repository but make sure you change the branding if you plan to distribute the client. You do not have the rights to use FossaMail's official branding.