You might be able to use "openal-soft" as a test-case.
$ rmadison -u debian -a source -s unstable openal-soft openal-soft | 1:1.9.563-1 | unstable | source openal-soft | 1:1.11.753-1 | unstable | source
$ rmadison -s lucid openal-soft openal-soft | 1:1.11.753-0ubuntu1 | lucid/universe | source
You might be able to use "openal-soft" as a test-case.
$ rmadison -u debian -a source -s unstable openal-soft
openal-soft | 1:1.9.563-1 | unstable | source
openal-soft | 1:1.11.753-1 | unstable | source
$ rmadison -s lucid openal-soft
openal-soft | 1:1.11.753-0ubuntu1 | lucid/universe | source