How does macOS open the document that you double-click/tap? First of 3 parts explaining what should happen and where it can go wrong.
UTIutility
Additional information is now shown for UTIs, it has its own custom app icon, and works wonderfully in Dark Mode.
What to do when you need to use Uniform Type Identifiers, only to discover that Apple’s reference manual hasn’t been updated for nearly 9 years: write an app!
The Eclectic Light Company 