Not sure where to send feedback about this, but i think an extra line is needed for the “What administrators need to do” section in the release notes (https://securedrop.org/news/securedrop-06-released).
The line missing is:
git fetch --tags
(mentioned here https://github.com/freedomofpress/securedrop/issues/2976)
Otherwise you get an error when trying to checkout 0.6
error: pathspec ‘0.6’ did not match any file(s) known to git.