20e cylinder head!

I've noticed on the head someone has cut grooves in the head where the valves are. Any ideas why this would of been done. I took it to road&rally today to get it checked for flatness incase it needed a skim he said never seen it before and dont know why it would of been done. https://uploads.tapatalk-cdn.com/202...eecbae6cd9.jpghttps://uploads.tapatalk-cdn.com/202...16398fe217.jpg

Sent from my SM-A105FN using Tapatalk

After a bit of research I believe these are signh grooves to help with combustion! Anyone know if it helps or best looking for a new head. It's a new head by the looks of it for a c20ne turbo build iam doing.

Anyone help.