The Migration Guide is here.

This ruleset needs to identify applications that have the quarkus-rest-client dependency
Source mode:
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-rest-client</artifactId>
</dependency>

<javaclass references="javax.ws.rs.client.Client">
<location>CONSTRUCTOR_CALL</location>
</javaclass>

Either declared in the POM, or within the jar file.
Potential issue, 1 SP

The Hint Message will be transcribe from the section Migration Guide (without the last sentence).

The Links are
https://docs.jboss.org/resteasy/docs/4.5.9.Final/userguide/html/ExceptionHandling.html#ResteasyWebApplicationException
https://quarkus.io/guides/rest-client
https://github.com/quarkusio/quarkus/wiki/Migration-Guide-1.12#rest-client-exceptions