They use the nerdfont patcher, which mainly mutilates fonts, and often breaks them trying to add the nerdfont glyphs. The nerdfonts project also distributes these broken fonts while ignoring the font licenses, and also ignoring the fact that fonts update and then nerdfonts refuses to patch and distribute the new version.

Many projects distribute both OTF and TTF versions, while nerdfonts only distributes the patched OTF version (as you, indeed, have noticed).

The upside is, since the patcher exists, you can just run it on your own fonts and do whatever you want.

I highly recommend avoiding nerdfonts altogether, disable it in any program you find it in, and also consider filing bugs with those projects to entice them to remove support entirely.

Unicode exists for a reason, and fonts should strive to cover as much of it as possible. Corporate logos and custom icons should not be enshrined into any font, not even as something niche like nerdfonts, even if nerdfonts lives entirely in the Unicode private use area (PUA).

2019 first release, replaced the old Windows Console as a default since Windows 11 22H2.