I think that for most common cases, [people don't want dependency generators
for `%doc` and `%license`](https://bugzilla.redhat.com/show_bug.cgi?id=964126).
Hence it might make sense to not process such files by default at all and add
an attr flag that can enable to process them, such as:
```
Yeah, emitting virtual file flags from dependency generator could be a useful
thing, %artifact is yet another such thing. Additionally file coloring could be
outsourced to the generators, that's where it really belongs. This just needs a
new API for the generator scripts, but this could be a
