/usr/share/bash-completion/completions/ is in lxc1 2.0.7-0ubuntu1~16.04.2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/bash-completion/completions/lxc-attach
/usr/share/bash-completion/completions/lxc-cgroup
/usr/share/bash-completion/completions/lxc-console
/usr/share/bash-completion/completions/lxc-copy
/usr/share/bash-completion/completions/lxc-create
/usr/share/bash-completion/completions/lxc-destroy
/usr/share/bash-completion/completions/lxc-device
/usr/share/bash-completion/completions/lxc-execute
/usr/share/bash-completion/completions/lxc-freeze
/usr/share/bash-completion/completions/lxc-info
/usr/share/bash-completion/completions/lxc-monitor
/usr/share/bash-completion/completions/lxc-snapshot
/usr/share/bash-completion/completions/lxc-start
/usr/share/bash-completion/completions/lxc-start-ephemeral
/usr/share/bash-completion/completions/lxc-stop
/usr/share/bash-completion/completions/lxc-unfreeze
/usr/share/bash-completion/completions/lxc-wait
/usr/share/bash-completion/completions/lxc1