/usr/share/zsh/functions/Completion/Linux/ is in zsh-common 5.1.1-1ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/zsh/functions/Completion/Linux/_acpi
/usr/share/zsh/functions/Completion/Linux/_acpitool
/usr/share/zsh/functions/Completion/Linux/_analyseplugin
/usr/share/zsh/functions/Completion/Linux/_brctl
/usr/share/zsh/functions/Completion/Linux/_btrfs
/usr/share/zsh/functions/Completion/Linux/_chrt
/usr/share/zsh/functions/Completion/Linux/_cryptsetup
/usr/share/zsh/functions/Completion/Linux/_ethtool
/usr/share/zsh/functions/Completion/Linux/_fuse_arguments
/usr/share/zsh/functions/Completion/Linux/_fuse_values
/usr/share/zsh/functions/Completion/Linux/_fusermount
/usr/share/zsh/functions/Completion/Linux/_ionice
/usr/share/zsh/functions/Completion/Linux/_ipset
/usr/share/zsh/functions/Completion/Linux/_iptables
/usr/share/zsh/functions/Completion/Linux/_iwconfig
/usr/share/zsh/functions/Completion/Linux/_losetup
/usr/share/zsh/functions/Completion/Linux/_lsusb
/usr/share/zsh/functions/Completion/Linux/_mdadm
/usr/share/zsh/functions/Completion/Linux/_mii-tool
/usr/share/zsh/functions/Completion/Linux/_modutils
/usr/share/zsh/functions/Completion/Linux/_mondo
/usr/share/zsh/functions/Completion/Linux/_nmcli
/usr/share/zsh/functions/Completion/Linux/_pkgtool
/usr/share/zsh/functions/Completion/Linux/_qdbus
/usr/share/zsh/functions/Completion/Linux/_rpmbuild
/usr/share/zsh/functions/Completion/Linux/_schedtool
/usr/share/zsh/functions/Completion/Linux/_ss
/usr/share/zsh/functions/Completion/Linux/_sshfs
/usr/share/zsh/functions/Completion/Linux/_strace
/usr/share/zsh/functions/Completion/Linux/_sysstat
/usr/share/zsh/functions/Completion/Linux/_tpb
/usr/share/zsh/functions/Completion/Linux/_tpconfig
/usr/share/zsh/functions/Completion/Linux/_tune2fs
/usr/share/zsh/functions/Completion/Linux/_uml
/usr/share/zsh/functions/Completion/Linux/_valgrind
/usr/share/zsh/functions/Completion/Linux/_vserver
/usr/share/zsh/functions/Completion/Linux/_wakeup_capable_devices
/usr/share/zsh/functions/Completion/Linux/_wpa_cli