extract
Recover the source file from an output file, verbatim.
The source is embedded in an HTML comment by default, so the output is its own backup — with nothing but the HTML file you can still get the .md back.
Not for files built with --no-embed-source
Those outputs do not carry the comment, and extract fails with exit 1.
When to turn embedding off: the output goes to someone external and the source contains notes or drafts they should not see. The cost is losing this recovery.
The size cost is measurable — run pamphlet build --verbose and read the "embedded source" line (measured on this repository's example: 3.8KB, 11% of the file).