Comment 3 for bug 148994

The components division is at the source level; for example the buildd machines are pulling build-dependencies only from allowed components when building source packages. It's possible to demote binary packages (such as module packages) to sub components, but not to build against sub components. IOW, to allow libquicktime to build against packages in multiverse, it must be in multiverse (or a copy of libquicktime, for example libquicktime-multiverse).