Leaving the specific letters aside, I wonder about this comment in <a href="https:&#x2F;&#x2F;github.com&#x2F;http2&#x2F;http2-spec&#x2F;issues&#x2F;101" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;http2&#x2F;http2-spec&#x2F;issues&#x2F;101</a>:<p>&quot;And the experimental data we have (what there is of it) suggests that we need to make this look like an unknown HTTP&#x2F;1.1 method (or two).&quot;<p>Anyone know what experimental data this refers to, and why this helps?  This gets encapsulated inside TLS; nothing should know about it except the endpoints, both of which need to understand HTTP&#x2F;2.