I believe it's "First Customer Shipment" and it's similar to what Microsoft call RTM "Release To Manufacture". You can see it mentioned in passing at the bottom

I believe it's "First Customer Shipment" and it's similar to what Microsoft call RTM "Release To Manufacture". You can see it mentioned in passing at the bottom of this page : https://blogs.oracle.com/patch/solaris-10-0508-update-5-patch-bundle https://blogs.oracle.com/patch/solaris-10-0508-update-5-patc...