thunderbird/thunderbird-android

This repository holds the source code for Thunderbird for Android, a free email app for Android phones. It lets you manage several email accounts in one place and offers a Unified Inbox option that combines messages from all your accounts into a single list. The README stresses privacy: the app is open source, meaning anyone can read and check its code, and the project states it does not treat your private data as a product to be sold. The app comes from the Thunderbird project, which is run under Mozilla, the nonprofit behind the Firefox browser. Thunderbird for Android is built on an older, well-established email app called K-9 Mail. The README explains that K-9 Mail joined the Thunderbird family in 2022 and became the foundation for this app, which is why the two look and behave almost the same. They share the same underlying code, with a few features turned on only for Thunderbird. K-9 Mail still exists separately for people who prefer it, and the README links to where you can get it. Most of the README is about getting and helping with the app rather than technical detail. You can download it from Google Play, from F-Droid, which is a store for open source Android apps, or from GitHub releases, among other sources. There is also a beta version for people who want to try new features before they are finished. The README then lists ways to get involved. You can search a knowledge base and support forum for help, report bugs on GitHub, suggest features, or join community chat channels on Matrix, a messaging network. Contributions are welcome in several forms: writing code in Kotlin, translating the app into other languages, or donating money, since the project says it is funded entirely by user contributions. It also notes some developer specifics, including a set of recorded architecture decisions kept in the repository, instructions for anyone making their own fork, and that the app is released under the Apache 2.0 license.