I think ubiquity installs recommended packages which are in main. But
mozc-utils-gui seems to have been moved to universe already:
$ rmadison mozc-utils-gui | grep -E 'cosmic|disco'
mozc-utils-gui | 2.23.2815.102+dfsg-2 | cosmic | amd64, arm64, armhf, i386
mozc-utils-gui | 2.23.2815.102+dfsg-2 | disco/universe | amd64, arm64, armhf, i386
mozc-utils-gui | 2.23.2815.102+dfsg-2build1 | disco-proposed/universe | amd64, arm64, armhf, i386
That ought to be the reason why it wasn’t installed for you, not the fact that it’s not yet in
So if nobody objects, I can fix your bug, i.e. adding
pkg_depends. But I don’t think that will make ubiquity install it. It will make Language Support pull it though.