/etc/ is in initramfs-tools 0.99ubuntu13.
This file is owned by root:root, with mode 0o755.
..
/etc/initramfs-tools/scripts/
/etc/initramfs-tools/scripts/init-bottom/
/etc/initramfs-tools/scripts/init-premount/
/etc/initramfs-tools/scripts/init-top/
/etc/initramfs-tools/scripts/local-bottom/
/etc/initramfs-tools/
/etc/initramfs-tools/scripts/local-premount/
/etc/initramfs-tools/scripts/local-top/
/etc/initramfs-tools/scripts/nfs-bottom/
/etc/initramfs-tools/scripts/nfs-premount/
/etc/initramfs-tools/scripts/nfs-top/
/etc/initramfs-tools/scripts/panic/
/etc/initramfs-tools/hooks/
/etc/initramfs-tools/conf.d/
/etc/initramfs-tools/initramfs.conf
/etc/initramfs-tools/update-initramfs.conf
/etc/kernel/
/etc/kernel/postinst.d/
/etc/kernel/postinst.d/initramfs-tools
/etc/kernel/postrm.d/
/etc/kernel/postrm.d/initramfs-tools
/etc/bash_completion.d/
/etc/bash_completion.d/initramfs-tools