Since version 0.2.1 Mavenzilla supports caching of HTTP repositories. The current implementation is quite simple.
Each URL is cached independently. That means, that not just one repository is cached, but only one URL. So, the first page -- the page where the groups are listed -- is cached very frequently. The page of each artifact is only cached when it is needed, independent from the type of the artifact. For each URL one cache file is generated, which is located in ${user.home}/.mavenzilla/cache/<url>.ser.