If i change the build folder (according to Issue 6470) than the results Page of Checkstyle (and Findbugs) shows the name of the new build folder (in my case .target) as project name. So the list shows me something like:

.target ...
Project1 ...
Project2 ...

And if i change the build folders of different modules in a multi-module build to .target all result-information of the different projects is found in the list under .target instead of an project-entry for each module. The screenshot shows an example checkstyle-resultpage.