I downloaded Terminess Nerd Font from brew, and was trying to set it as the font in kitty terminal. No method worked, whether editing the config directly or using kitten choose-fonts; the terminal would still use Menlo. Despite this, both Terminess Nerd Font and Terminess Nerd Font Mono would render in the kitten's preview window.
After some searching, I came across this issue, where kitty terminal must have a fixed width font for its "main" font and began enforcing this correctly around August 2024. This made me wonder: Is Terminess (specifically, its mono variation) actually a monospaced font according to MacOS? If it were not, that would explain why I couldn't use it as my main font, even though it did render in the kitten choose-fonts preview window.
I found this question which would let you list all monospace fonts in Font Book, but the UI option pointed out in the top answer appears to no longer exist, and I did not find a way to search for "monospaced" or "fixed width" as a font feature or style. Both Terminess and Terminess Mono are in Font Book, and pass Font Book's validation, but I have no other information about whether either is a monospaced font according to the operating system. Or to kitty, for that matter, which I'll admit could be the actual issue.
Is there another way to verify whether a font is actually monospaced in MacOS? Or does the fontbook feature to list monospaced fonts still exist in a new location?