/usr/share/live/build/hooks/ is in live-build 3.0~a57-1ubuntu34.
This file is owned by root:root, with mode 0o755.
..
/usr/share/live/build/hooks/001-update-apt-file-cache.chroot
/usr/share/live/build/hooks/002-update-apt-xapian-index.chroot
/usr/share/live/build/hooks/003-update-mlocate-database.chroot
/usr/share/live/build/hooks/004-remove-dbus-machine-id.chroot
/usr/share/live/build/hooks/005-remove-gnome-icon-cache.chroot
/usr/share/live/build/hooks/006-remove-openssh-server-host-keys.chroot
/usr/share/live/build/hooks/007-remove-python-py.chroot
/usr/share/live/build/hooks/008-remove-udev-persistent-rules.chroot
/usr/share/live/build/hooks/009-remove-apt-sources-lists.chroot
/usr/share/live/build/hooks/100-build-wubildr.binary