I think would be ready if it passed IDnits. I found the document good read and found no sinkholes in it. Pointing up two implementations was also great. The Proto Write-up seems not be up to date with what IDnits says e.g., when it comes to downrefs, which is what the IDnits complain about. A couple of editorials: Lines 118-119 says: "This takes this.." I would reword to something like: "This document takes using NXDOMAIN information for more effective caching further." Lines 396 and 397 uses "is NOT" and "IS making". I would use lower case here. No reason to use capitalized and still non-RFC2119 language. Line 407 is would be great to indicate since which version of Unbound support has been in place.