This method is called within the info.magnolia.module.delta.WebXmlConditionsUtil.filterMustBeRegisteredWithCorrectDispatchers method, to test that there are REQUEST and FORWARD dispatchers configured in the web.xml file before starting/installing the core module.
However, in our case we have added the INCLUDE dispatcher in order to enable inclusion of magnolia content into other web apps. Since this test only passes if there are only these two dispatchers configured (with optional "ERROR"), it fails even if these 2 dispatchers are present along with the INCLUDE. This prevents the core module from installing on bootstrapped startup.
I think it should only test the mandatory presence of REQUEST and FORWARD, and not validate additional dispatchers.