Distributions are the bottom-most workloads in the inheritance chain. Distributions are implemented as a python package included with the board. Users will rarely interact with distributions directly since distributions may require significant and tricky modifications to work with the board. Instead, they should inherit from the base workloads included with the board. The one exception is through the distro option in your workload that allows you to tweak distro-specific options (e.g. add/remove packages).