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.
Recent comments
Before switching SEO modules, I’d check Google Search Console to see why the remaining pages aren’t being indexed. Pages marked as “Discovered currently not indexed” may need stronger internal...
SEO tools
there is no error, it gently renames the file
How to upload js and gz files
Could be a trivial thing like Permissions -> Access administration bar (for a role)?
User seeing admin stuff