Font suitcases?
My knowledge of fonts dates back to the OS9 days. Unfortunately, it hasn't been updated much since then.
I have a copy of FrizQuadrata from an archive/backup. It's got a suitcase icon. When I trigger Quick Look, it looks great; a nice, fullscreen window of all the characters comes up.
When I double click it, however, I get the clueless message:
There is no application set to open the document "FrizQuadrata Rm/Bd BT.tt"
Search the App Store for an application that can open this document, or choose an existing application on your computer_
[Choose Application...] [Cancel] [Search App Store]
I thought the way you install fonts on OS X is by double-clicking?
Mac mini, macOS 10.15