### What needs to get done * Add an environment variable `SNAPCRAFT_DISABLE_FILE_BASED_KEYRING`. * Document how to disable the file-based keyring backend. ### Why it needs to get done Tools like [`ubuntu-image`](https://snapcraft.io/install/ubuntu-image/ubuntu) depend on keys created by snapcraft. If snapcraft uses a file-based backend, then other tools will have no access to those keys in the system keyring. The user experience is confusing, because `snapcraft list-keys` will show keys that aren't accessible from the system keyring.