guile: warning: failed to install locale
environment variable `PATH' set to `/gnu/store/qx460n53ww7vwnm9g6vp5jv5s9s403v3-gzip-1.10/bin:/gnu/store/wygi0gsdiw66ib8wgq16qq4cfy5zlvdr-tar-1.32/bin'
hint: Using 'master' as the name for the initial branch. This default branch name
hint: is subject to change. To configure the initial branch name to use in all
hint: of your new repositories, which will suppress this warning, call:
hint: 
hint: 	git config --global init.defaultBranch <name>
hint: 
hint: Names commonly chosen instead of 'master' are 'main', 'trunk' and
hint: 'development'. The just-created branch can be renamed via this command:
hint: 
hint: 	git branch -m <name>
Initialized empty Git repository in /gnu/store/mhz8k1x0y8mmgzl8q2dac2g2mmag2vc0-ruby-concurrent-1.1.5-checkout/.git/
From https://github.com/ruby-concurrency/concurrent-ruby
 * tag               v1.1.5     -> FETCH_HEAD
Note: switching to 'FETCH_HEAD'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at ffed3c3 Doc update