That looks nice and shiney
The groove and the hole are a safety feature so that if the head gasket blows the exhaust gases go into the groove , up the hole then out through a special hollow bolt that goes through the tinware then into the head in that M10 threaded hole shown in the picture. Without that feature if the head gasket goes and you have the heater on then you will be pumping carbon monoxide into the cabin
Some people have over skimmed the head and that groove has disappeared. Also if you go for a big bore kit as the diameter of the piston gets so close to the groove then that groove has to be filled. I did post a picture of the head from my 795ccs where the groove had been welded up some time ago.