/usr/share/initramfs-tools/ is in initramfs-tools-core 0.122ubuntu8.14.
This file is owned by root:root, with mode 0o755.
..
/usr/share/initramfs-tools/conf-hooks.d/
/usr/share/initramfs-tools/conf.d/
/usr/share/initramfs-tools/hook-functions
/usr/share/initramfs-tools/hooks/
/usr/share/initramfs-tools/hooks/busybox
/usr/share/initramfs-tools/hooks/compcache
/usr/share/initramfs-tools/hooks/fixrtc
/usr/share/initramfs-tools/hooks/framebuffer
/usr/share/initramfs-tools/hooks/fsck
/usr/share/initramfs-tools/hooks/klibc
/usr/share/initramfs-tools/hooks/resume
/usr/share/initramfs-tools/hooks/thermal
/usr/share/initramfs-tools/init
/usr/share/initramfs-tools/modules
/usr/share/initramfs-tools/modules.d/
/usr/share/initramfs-tools/scripts/
/usr/share/initramfs-tools/scripts/functions
/usr/share/initramfs-tools/scripts/init-top/
/usr/share/initramfs-tools/scripts/init-top/all_generic_ide
/usr/share/initramfs-tools/scripts/init-top/blacklist
/usr/share/initramfs-tools/scripts/init-top/framebuffer
/usr/share/initramfs-tools/scripts/init-top/keymap
/usr/share/initramfs-tools/scripts/local
/usr/share/initramfs-tools/scripts/local-premount/
/usr/share/initramfs-tools/scripts/local-premount/fixrtc
/usr/share/initramfs-tools/scripts/local-premount/resume
/usr/share/initramfs-tools/scripts/nfs