Upon manually deleting the directory and re-installing the package, I see some surprising omissions that I expect are due to third-party packages installing their own scripts into the /usr/share/bash-completion/completions folder instead of into /etc/bash_completion.d/ . Does that need to be separate bug reports (policy violation) against each of those packages? My list has 159 entries. It's quite possible that there would be more, had I installed every single package in the debian repositories ...
adb addpart apt apt-file apt-offline apt-show-versions atool axi-cache blkdiscard blkid blockdev btrfs bwrap bzr chcpu chmem chrt ctrlaltdel ddgr-completion.bash debconf debconf-show debget debian-goodies.pkgnames debmany deborphan debtags delpart dhomepage dmesg falkon fallocate fastboot fdformat findfs findmnt firecfg firejail firemon flock fsck fsck.cramfs fsck.minix fsfreeze fstrim gapplication gdbus getopt gio git gitk gresource gsettings hub hwclock insserv ionice ipcmk ipcrm ipcs isoquery isosize kmod last ldattach libreoffice logger loginctl losetup lsblk lscpu lsipc lslocks lslogins lsmem lsns lxc lxc-attach lxc-cgroup lxc-console lxc-copy lxc-create lxc-destroy lxc-device lxc-execute lxc-freeze lxc-info lxc-monitor lxc-snapshot lxc-start lxc-stop lxc-unfreeze lxc-wait lynis mcookie mdbtools mesg mkfs mkfs.bfs mkfs.cramfs mkfs.minix mkswap more mount mountpoint namei nnn-completion.bash nsenter openvpn partx perf pivot_root pkcon prlimit pygmentize qpdf R rake raw readprofile redis-cli renice resizepart rev rtcwake script scriptreplay setarch setsid setterm source-highlight su svn svnadmin svndumpfilter svnlook svnversion swaplabel swapoff swapon taskset tc tig udisksctl ufw umount unshare update-initramfs update-java-alternatives utmpdump wall wdctl whereis which-pkg-broke whiptail wipefs wxmaxima youtube-dl zathura zramctl -- hkp://keys.gnupg.net CA45 09B5 5351 7C11 A9D1 7286 0036 9E45 1595 8BC0