snapcraft: 7.1.3 base: core20 snapcraft.yaml: package-repositories: - type: apt ppa: snappy-dev/image This results in: snapcraft-ppa-snappy-dev_image.sources with the following content: Types: deb URIs: http://ppa.launchpad.net/snappy-dev/image/ubuntu Suites: focal Components: main Architectures: arm64 If "architectures" was not specified in "package-repositories", snapcraft should not assume it, and omit "Architectures" in the generated source file.