Zimpley ships as a direct-download Mac app. Each stable release is signed, notarized and published once so the website download, release notes and Sparkle appcast all point to the same build.
The release record stores the version, build number, minimum macOS version, DMG size and checksum, and the Sparkle EdDSA signature. The Mac app reads that signed appcast through its configured feed and public key, keeping manual downloads and in-app updates aligned.