They’re bash/shell- and bin-dependent commands rather than Git commands. I use Nushell.
Transformed to Nushell commands:

• The 20 most-changed files in the last year:
  git log --format=format: --name-only --since="1 year ago" | lines | str trim | where (is-not-empty) | uniq --count | sort-by count --reverse | take 20
• Who Built This:
  git shortlog -sn --no-merges
git shortlog -sn --no-merges --since="6 months ago"
• Where Do Bugs Cluster:
  git log -i -E --grep="fix|bug|broken" --name-only --format='' | lines | str trim | where (is-not-empty) | uniq --count | sort-by count --reverse | take 20
• Is This Project Accelerating or Dying:
  git log --format='%ad' --date=format:'%Y-%m' | lines | str trim | where (is-not-empty) | uniq --count
• How Often Is the Team Firefighting:
  git log --oneline --since="1 year ago" | find --ignore-case --regex 'revert|hotfix|emergency|rollback'

/edit: Looks like the lines have whitespace or sth. Replaced lines --skip-empty with lines | str trim | where (is-not-empty).

def "gits most-changed-files" [] { git log --format=format: --name-only --since="1 year ago" | lines | str trim | where (is-not-empty) | uniq --count | sort-by count --reverse | take 20 }
def "gits who" [] { git shortlog -sn --no-merges }
def "gits who6m" [] { git shortlog -sn --no-merges --since="6 months ago" }
def "gits fixes" [] { git log -i -E --grep="fix|bug|broken" --name-only --format='' | lines | str trim | where (is-not-empty) | uniq --count | sort-by count --reverse | take 20 }
def "gits aliveness" [] { git log --format='%ad' --date=format:'%Y-%m' | lines | str trim | where (is-not-empty) | uniq --count }
def "gits firefighting" [] { git log --oneline --since="1 year ago" | find --ignore-case --regex 'revert|hotfix|emergency|rollback' }

This would have no effect in my team where everyone does whatever they want in git lol

Ahh the famous git commands such as sort, uniq, head, and grep.

Gonna have to try that out. I think it would have told interesting stories on some past repos.

I wish '‘co-authored by AI’ was easy to flag in vcs.

Super cool