There was a PR (#4370) to add i686/i386 support for Vaultwarden.
That specific PR was not a viable way of adding this.

This PR adds extra architectures for Debian based containers which we
will not support by default. Those images will not be build and pushed
to our container registries.

Added the following architectures:
 - linux/386
 - linux/ppc64le
 - linux/s390x

Again, there will be no major support for these architectures, but it
will allow people who use these architectures to build a Debian based
binary more easily