/usr/share/subversion/hook-scripts/ is in subversion-tools 1.8.8-1ubuntu3.3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/subversion/hook-scripts/commit-access-control.cfg.example
/usr/share/subversion/hook-scripts/commit-access-control.pl
/usr/share/subversion/hook-scripts/commit-email.pl
/usr/share/subversion/hook-scripts/commit-email.rb
/usr/share/subversion/hook-scripts/control-chars.py
/usr/share/subversion/hook-scripts/log-police.py
/usr/share/subversion/hook-scripts/mailer/
/usr/share/subversion/hook-scripts/mailer/mailer.conf.example
/usr/share/subversion/hook-scripts/mailer/mailer.py
/usr/share/subversion/hook-scripts/persist-ephemeral-txnprops.py
/usr/share/subversion/hook-scripts/svn2feed.py
/usr/share/subversion/hook-scripts/svnperms.conf.example
/usr/share/subversion/hook-scripts/svnperms.py
/usr/share/subversion/hook-scripts/validate-extensions.py
/usr/share/subversion/hook-scripts/validate-files.conf.example
/usr/share/subversion/hook-scripts/validate-files.py
/usr/share/subversion/hook-scripts/verify-po.py