/usr/share/bash-completion/ is in devscripts 2.17.6+deb9u2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/bash-completion/completions/
/usr/share/bash-completion/completions/bts
/usr/share/bash-completion/completions/build-rdeps
/usr/share/bash-completion/completions/chdist
/usr/share/bash-completion/completions/checkbashisms
/usr/share/bash-completion/completions/dch
/usr/share/bash-completion/completions/dcontrol
/usr/share/bash-completion/completions/dd-list
/usr/share/bash-completion/completions/debc
/usr/share/bash-completion/completions/debchange
/usr/share/bash-completion/completions/debcheckout
/usr/share/bash-completion/completions/debdiff
/usr/share/bash-completion/completions/debi
/usr/share/bash-completion/completions/debsign
/usr/share/bash-completion/completions/debsnap
/usr/share/bash-completion/completions/debuild
/usr/share/bash-completion/completions/dget
/usr/share/bash-completion/completions/dscextract
/usr/share/bash-completion/completions/dscverify
/usr/share/bash-completion/completions/getbuildlog
/usr/share/bash-completion/completions/grep-excuses
/usr/share/bash-completion/completions/list-unreleased
/usr/share/bash-completion/completions/mass-bug
/usr/share/bash-completion/completions/mk-build-deps
/usr/share/bash-completion/completions/mk-origtargz
/usr/share/bash-completion/completions/pkgnames
/usr/share/bash-completion/completions/plotchangelog
/usr/share/bash-completion/completions/pts-subscribe
/usr/share/bash-completion/completions/pts-unsubscribe
/usr/share/bash-completion/completions/rc-alert
/usr/share/bash-completion/completions/rmadison
/usr/share/bash-completion/completions/transition-check
/usr/share/bash-completion/completions/uscan
/usr/share/bash-completion/completions/uupdate
/usr/share/bash-completion/completions/what-patch
/usr/share/bash-completion/completions/who-uploads
/usr/share/bash-completion/completions/whodepends
/usr/share/bash-completion/completions/wnpp-alert
/usr/share/bash-completion/completions/wnpp-check