Bug#942016: libopencv3.2-java is archtecture: all, but not M-A: foreign

[Лухнов Андрей Олегович]

Package: libopencv3.2-java
Version: 3.2.0+dfsg-6
Severity: important

Dear Maintainer,

for some reason libopencv3.2-java is archtecture: all, but not marked as M-A:
foreign.

this blocks cross-building of packages (or I'm doing something totally wrong).

My package (a private one) depends on libgstreamer-plugins-bad1.0-dev and
everything compiles just fine if I compile for native arch.

but during cross-compilation build-deps installation fails with the following:

The following packages have unmet dependencies:
 libgstreamer-plugins-bad1.0-dev:armel : Depends: libopencv-dev:armel (>=
2.3.0) but it is not going to be installed

which leads me to:

libopencv-dev:armel : Depends: libopencv3.2-java:armel (= 3.2.0+dfsg-6) but it
is not installable
                       Recommends: opencv-data:armel but it is not installable

and...

E: Package 'libopencv3.2-java:armel' has no installation candidate

able to reproduce it on buster, bullseye and sid.

May be, it wasn't marked for a reason, but I haven't found it yet.
Any hints would be appreciated!

Best,
Andrey