Intuitively, I think of the "build" step producing part-specific build directories, "stage" using those those part-specific directories to create a single stage area, and "snap" using the stage area to create a directory to snappify. With this workflow, I came up with the following YAML snippet: # ... parts:   foo:     plugin: cmake     source: src     stage:       - -documentation # ... Looking at this YAML combined with my understanding from above, I figure the documentation will not end up in the staging area, and since the "snap" step pulls from the staging area, the documentation will not end up in the final .snap either. However, that's incorrect-- the "snap" step errors out complaining about not being able to find files under the documentation/ folder. This implies to me that either my understanding is fundamentally flawed, or this is a bug causing the filesets to come from the parts instead of the staging area. It requires a YAML like this, which seems redundant: # ... parts: foo: plugin: cmake source: src stage: - -documentation snap: - -documentation # ...