Bug#901030: plain registrations on the container host
As I said in https://salsa.debian.org/salsa/support/issues/88:
Diving into the binfmt docs a bit, it seems to me that the binfmt
registrations are just a lookup table of sorts that provide a path to an
executable based on magic or extension rules. So if the container host
has all the relevant rules in place, shouldn't the container itself just
be able to read them and use them?
That could be achieved either by installing packages like jarwrapper on
the container host, or just by echoing the binfmt rules to
/proc/sys/fs/binfmt_misc/register in a startup script.