System Font Not Appearing in Font Book; Still Works
I'm on macOS 10.15.4 so Iowan Old Style.ttc is located in the read-only /System/Library/Fonts/Supplemental/. It's there. I ran a validation on it, and it is perfectly fine. No problems.
Iowan Old Style displays properly in documents and web pages. I created a web page to make sure it was using my local font and not a woff. It is using the local font.
But Iowan Old Style does not appear in Font Book or the font-selection window for any application.
I made sure there were no other copies of Iowan Old Style on my machine. There aren't.
I deleted font caches. I rebooted in recovery mode and ran:
atsutil databases -remove
I rebooted back to my normal account, and it still did not work.
I trashed all font and Font Book related preferences. Still did not work.
I put a copy of Iowan Old Style.ttc in ~/Library/Fonts/. Nope, that didn't appear in Font Book either. I extracted the ttf files from the ttc file. Those don't appear in Font Book either.
I rebooted in safe-mode, logged into my clean admin account, and found that Iowan Old Style doesn't appear in Font Book for that account either. It must be a problem at the system level rather than the user level.
Does anyone have any ideas? I've exhausted all of the solutions I know of.
Thank you
MacBook Pro 15", macOS 10.15