1Y = Comprehensively Implemented, to the point appropriate for resolved
2D = Comprehensively Implemented, by a dependency of resolved
3! = Missing and something we might want to implement
4~ = Needs no explicit support or doesn't apply
5? = Is this relevant today?
6  = We are working on this
7
8Y https://tools.ietf.org/html/rfc1034 → DOMAIN NAMES - CONCEPTS AND FACILITIES
9Y https://tools.ietf.org/html/rfc1035 → DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION
10? https://tools.ietf.org/html/rfc1101 → DNS Encoding of Network Names and Other Types
11Y https://tools.ietf.org/html/rfc1123 → Requirements for Internet Hosts — Application and Support
12~ https://tools.ietf.org/html/rfc1464 → Using the Domain Name System To Store Arbitrary String Attributes
13Y https://tools.ietf.org/html/rfc1536 → Common DNS Implementation Errors and Suggested Fixes
14Y https://tools.ietf.org/html/rfc1876 → A Means for Expressing Location Information in the Domain Name System
15Y https://tools.ietf.org/html/rfc2181 → Clarifications to the DNS Specification
16Y https://tools.ietf.org/html/rfc2308 → Negative Caching of DNS Queries (DNS NCACHE)
17Y https://tools.ietf.org/html/rfc2782 → A DNS RR for specifying the location of services (DNS SRV)
18D https://tools.ietf.org/html/rfc3492 → Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA)
19Y https://tools.ietf.org/html/rfc3596 → DNS Extensions to Support IP Version 6
20Y https://tools.ietf.org/html/rfc3597 → Handling of Unknown DNS Resource Record (RR) Types
21Y https://tools.ietf.org/html/rfc4033 → DNS Security Introduction and Requirements
22Y https://tools.ietf.org/html/rfc4034 → Resource Records for the DNS Security Extensions
23Y https://tools.ietf.org/html/rfc4035 → Protocol Modifications for the DNS Security Extensions
24! https://tools.ietf.org/html/rfc4183 → A Suggested Scheme for DNS Resolution of Networks and Gateways
25Y https://tools.ietf.org/html/rfc4255 → Using DNS to Securely Publish Secure Shell (SSH) Key Fingerprints
26Y https://tools.ietf.org/html/rfc4343 → Domain Name System (DNS) Case Insensitivity Clarification
27~ https://tools.ietf.org/html/rfc4470 → Minimally Covering NSEC Records and DNSSEC On-line Signing
28Y https://tools.ietf.org/html/rfc4501 → Domain Name System Uniform Resource Identifiers
29Y https://tools.ietf.org/html/rfc4509 → Use of SHA-256 in DNSSEC Delegation Signer (DS) Resource Records (RRs)
30~ https://tools.ietf.org/html/rfc4592 → The Role of Wildcards in the Domain Name System
31~ https://tools.ietf.org/html/rfc4697 → Observed DNS Resolution Misbehavior
32Y https://tools.ietf.org/html/rfc4795 → Link-Local Multicast Name Resolution (LLMNR)
33Y https://tools.ietf.org/html/rfc5011 → Automated Updates of DNS Security (DNSSEC) Trust Anchors
34Y https://tools.ietf.org/html/rfc5155 → DNS Security (DNSSEC) Hashed Authenticated Denial of Existence
35Y https://tools.ietf.org/html/rfc5452 → Measures for Making DNS More Resilient against Forged Answers
36Y https://tools.ietf.org/html/rfc5702 → Use of SHA-2 Algorithms with RSA in DNSKEY and RRSIG Resource Records for DNSSEC
37Y https://tools.ietf.org/html/rfc5890 → Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework
38Y https://tools.ietf.org/html/rfc5891 → Internationalized Domain Names in Applications (IDNA): Protocol
39Y https://tools.ietf.org/html/rfc5966 → DNS Transport over TCP - Implementation Requirements
40Y https://tools.ietf.org/html/rfc6303 → Locally Served DNS Zones
41Y https://tools.ietf.org/html/rfc6604 → xNAME RCODE and Status Bits Clarification
42Y https://tools.ietf.org/html/rfc6605 → Elliptic Curve Digital Signature Algorithm (DSA) for DNSSEC
43  https://tools.ietf.org/html/rfc6672 → DNAME Redirection in the DNS
44! https://tools.ietf.org/html/rfc6731 → Improved Recursive DNS Server Selection for Multi-Interfaced Nodes
45Y https://tools.ietf.org/html/rfc6761 → Special-Use Domain Names
46  https://tools.ietf.org/html/rfc6762 → Multicast DNS
47  https://tools.ietf.org/html/rfc6763 → DNS-Based Service Discovery
48~ https://tools.ietf.org/html/rfc6781 → DNSSEC Operational Practices, Version 2
49Y https://tools.ietf.org/html/rfc6840 → Clarifications and Implementation Notes for DNS Security (DNSSEC)
50Y https://tools.ietf.org/html/rfc6891 → Extension Mechanisms for DNS (EDNS(0))
51Y https://tools.ietf.org/html/rfc6944 → Applicability Statement: DNS Security (DNSSEC) DNSKEY Algorithm Implementation Status
52Y https://tools.ietf.org/html/rfc6975 → Signaling Cryptographic Algorithm Understanding in DNS Security Extensions (DNSSEC)
53Y https://tools.ietf.org/html/rfc7129 → Authenticated Denial of Existence in the DNS
54Y https://tools.ietf.org/html/rfc7646 → Definition and Use of DNSSEC Negative Trust Anchors
55~ https://tools.ietf.org/html/rfc7719 → DNS Terminology
56Y https://tools.ietf.org/html/rfc8080 → Edwards-Curve Digital Security Algorithm (EdDSA) for DNSSEC
57
58Also relevant:
59
60  https://www.iab.org/documents/correspondence-reports-documents/2013-2/iab-statement-dotless-domains-considered-harmful/
61