I've set up an `override-pull` scriptlet for some snaps to automatically parse the upstream release page and download & extract the latest release tarball to SNAPCRAFT_PART_SRC, as the actual source URL is determined in the scriptlet the `source` property isn't really required but Snapcraft currently will still complain: * Failed to load plugin: properties failed to load for main: 'source' is a required property * Failed to pull source: unable to determine source type of 'Parsed automatically at main-pull scriptlet' ('Parsed automatically at main-pull scriptlet' is a dummy value set in snapcraft yaml) Some thoughts: * The checks probably should be deferred to the point where the snapcraft-managed-pull is triggered * `snapcraftctl set-source`?