I am trying to deobfuscate nms manually. The problem is that in the mappings file things are referenced like net/minecraft/unmapped/C_bdwnwhiu or f_ajnajowl but when I open the jar file I only see: a, b, c, etc.
Yes. This is expected. We cannot distribute the Minecraft jar, so we are only able to provide mappings for it.
To remap Minecraft, you need to use Tiny Remapper. You can see a usage of that here.
Once that is done, the Minecraft jar will be remapped and have the names you want.
Where do I get the tiny file?
ok I found them, but how do I use the tiny-remapper CLI?