Clover forks a build (in the validate phase) which seems to go at least as far as the verify phase, which causes the checkstyle plugin to be executed. This in turn causes errors when generating a site, because the clover-generated code doesn't necessarily comply with our checkstyle rules (or our src/test suppression isn't applied, because the clover-instrument test sources are generated under target/clover/src-test)

At the time of writing, it is unclear "how far" that forked build goes, nor whether we could (and should) control that (i.e make it stop after test execution?). So all we can do is add target/clover in our checkstyle suppressions.