In Web subsystem there is possible to define protocol either via its API name (e.g. HTTP/1.1, where it is taken default implementation of given API) or via FQCN.

In case of HTTP/1.1 there are several implementations:
JIO => org.apache.coyote.http11.Http11Protocol - default protocol
NIO2 => org.apache.coyote.http11.Http11NioProtocol - required to be used to be able to use WebSockets
APR (default with natives) => org.apache.coyote.http11.Http11AprProtocol

The :migrate operation should also recognize these FQCN as valid HTTP/HTTPS protocols and migrate them correctly.

Note: in case of AJP there are these FQCN:
org.apache.coyote.ajp.AjpAprProtocol - AJP with natives enabled
org.apache.coyote.ajp.AjpProtocol AJP without natives