I want to change admin panel links & this is the only thread I can find on google.

I will never need the "extras" dropdown & I want to remove it from the list--

I'm trying to simplify things on the panel, so they are not as complex, by removing things I completely don't need (and will never need)

I can't figure out where the base files are for this, so I can remove this part of my admin.

Does someone know where the base files are for the admin dropdown lists?