Font Book reports "serious problems" with Code 2000? I just downloaded Code 2000 from Wayback Machine but when I tried to install it Font Book reported a serious error but no further details.

Anyone know what might be the problem? Are there any online resources that allows me to verify a font's integrity and hopefully could give me some more details about any potential issues?
In my experience Font Book warnings rarely have any real consequences.

It's also hard to imagine any issues that could not be easily fixed by just removing the font.  Install it manually in Home/Library/Fonts and see if you find any problems.

To get to Home/Library, hold down the option key while doing Finder > Go.

If your goal is to ensure complete Unicode coverage, I suspect MacOS already has more of this than the very old Code 2000.  To expand coverage beyond what Apple offers, I would recommend the Google Noto fonts and Symbola.

To see what font has a specific character when Apple's Character Viewer is empty, try Fileformat.