Whats this red bone and how do i remove it please ?

The red selected bone in the middle… I cant select it, it doesnt have name or anything, idk what to do… How do I remove or smthg please

It looks like you separated that bone from the armature (pressing P will do that)

If you go back to object mode, you can select and delete that bone.

To repair your armature, select the two ends where the bone used to connect and press F to recreate that bone.