The default entityresolver tries to resolve the XHTML 1.1 DTD occasionally, which due to the w3.org server's flakiness could take some time, or may hang even the build.
The plugin should really just bundle this basic DTD and use a custom EntityResolver to resolve this entity. Upon further need this resolver could be used to overcome similar problems with other schemas/DTDs.
Actually it seems like this was more of a config issue on my end. Basically my includes was just too wide and the plugin started to analyze some random XHTML files...
Closing as a not a defect for now :)
The default entityresolver tries to resolve the XHTML 1.1 DTD occasionally, which due to the w3.org server's flakiness could take some time, or may hang even the build. The plugin should really just bundle this basic DTD and use a custom EntityResolver to resolve this entity. Upon further need this resolver could be used to overcome similar problems with other schemas/DTDs.