Default open in?

I came here looking for how to make Taskpaper re-open files by default, but I think I found a different issue.

When I Get Info on my list: Notes.taskpaper, I don’t see Taskpaper as an application to pick from.

I’ve got version 3.3.2, and its Info.plist Document types only com.taskpaper.txt and public.data. I would expect to see an entry for taskpaper directly.