Build from source
The build process is pretty straight-forward. You need to have Flutter installed on your system.
The automated build process is done using GitHub Actions. You may find the workflow here. The workflow builds the app for all supported platforms & uploads the artifacts to the release page.
On Linux, a Flutter executable with different environment variables is used to build the app for different distributions. This tells the app how the system is configured and how it should install updates. To run for Linux, you need to provide the following environment variables based on your system, where [DISTRO_ENV]can be appimage(AppImage), deb(Debian), rpm(RedHat), tar.gz(Tarball) or pi(Raspberry Pi).