The current development work and git history of documentation is in the dafny-lang/dafny repository, in the docs folder.

The dafny-lang/dafny.github.io repo is the target for https://dafny.org and is the entry point to all the user-facing documentation about Dafny.

At the top-level is just the index.html landing page, supporting files (e.g., images) and files needed for the Github markdown translation.

Sub-folders contain snapshots of the Dafny documentation at the time of each release (beginning with 3.9.0). Each snapshot is in its own folder, e.g. dafny.org/vX.Y.Z, with latest containing the most recent, and dev redirecting to the development docs.