The --open flag is now more of a 'force' open. When mix docs.dash is called, the docset is opened automatically, unless a docset with the exact name already exists (in that case, the docs update under the hood, but do not need to be re-opened in Dash for the updates to be realized).
The --name NAME param now defaults to setting umbrella project names to the result of File.cwd!() |> Path.basename(), as this is likely the desired project name anyway.
An --abbr ABBR option can be passed to set a custom abbreviation. This can also be edited in Dash's preferences pane by hand. This only works when the docset is first added to Dash - after that, it must be updated via Dash or fully removed and readded.