Dear Plutten22,
This module can be with the name "extra product tab " or "product tab".
You may find it via search in the folder modules :"hookDisplayProductTab" or "hookDisplayProductTabContent". Note that the words DisplayProductTab definitely should be.
If you fail to find it, so this block is created not by hooks, but with the help of class override. In this case you should look for it in the folder override using the "summary" or "product tab" key words.
If you still need help, just contact us.
Best regards, Alt-team.