I do not think that there is any sense in having separate metapackages
for Architecture=all. The metapackages will be installed on a certain
architecture. For this architecture (i.e. amd64) you have a metapackage
for instance
med-bio_<version>_amd64.deb
there is no way to install any package
med-bio_<version>_all.deb
in parallel. So for every single architecture we need to create
metapackages featuring the packages for this architecture plus those
packages that are architecture = all which I expressed in my original
examle query in sql/blendsd_change_dependency by
... architecture in ('$3', 'all' )) ...
and which in your python code properly was turned into
... architecture in ('{2}', 'all' )) ...
There is no point at all to turn this into
architecture in ('all', 'all' ))
because there is no practical relevance for such a metapackage.