Change an output format

outputs: is a list. Lists append by default, so use $replace when a fragment should swap the inherited outputs instead of adding another artifact.

# image.yaml
outputs:
  - format: cosi

# by-edition/pro.yaml
outputs:
  $replace:
    - format: raw

To add an extra output instead, use normal list syntax:

# by-edition/debug.yaml
outputs:
  - format: qcow2

A build produces one artifact per selected cell × output. Valid formats are listed in output formats.