With the discussion in #131 which brought up a point about sub-themes, I decided it was a good time to point out that parent and sub-themes have never had a good UX feeling because the UI was never designed to incorporate them.
Proposed solution
What I propose is to slightly re-design the theme overview page and move the title of each theme into a "group" heading to allow a theme with sub-themes to all be housed together.
Mockup Example:

Draft of feature description for Press Release (1 paragraph at most)
The Backdrop theme overview page has been tweaked to group sub-themes together with their parent themes to create a better UI experience.
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