I recently picked up a new classe 8 project machine and as i have been going through the parts and sorting things out i noticed that the bolt on the group head appears to have been drilled out or something to that affect. Looks like a small machine screw and some sealant was added, the brass itself also looks quite stripped.

can anyone suggest as to why this would have been done, im still looking for parts diagrams to tell me whats behind that brass bolt.