Question about bash completion directory

[iquiw <iku.iwasa%gmail.com@localhost>]

Hi,

Sorry if this mailing list is not proper one.

I maintain some pkgsrc-wip packages and wonder which directory should
be used to install bash completion scripts.
In pkgsrc, there are at least 4 directories where some packages use to
install bash completion scripts.

(a) /usr/pkg/share/bash-completion/completions
(b) /usr/pkg/share/bash-completion.d
(c) /usr/pkg/share/bash_completion.d
(d) /usr/pkg/etc/bash_completion.d

(a) is most widely (over 20) used one. As of now, I'm using this.
(b) is used by 3 packages. audio/lilv, net/youtube-dl and textproc/jo.
(c) is used by 3 packages. benchmarks/phoronix-test-suite,
chat/ejabberd and sysutils/etckeeper.
(d) seems to be used by lang/rust only ("cargo").

Problem of (a) is that the directory is used by shells/bash-completion
package also.
If shells/bash-completion adds new files, conflict may happen.
(b) and (c) are not loaded from
/usr/pkg/share/bash-completion/bash_completion script by default.
So I think (d) could be the right choice, but not widely used now.

Which directory should be used?

Thanks in advance.
iku