In the new release which should drop today, I've both increased the strictness of the cache so the cache size should be smaller and also added a very minimal cache viewer in settings. This should at least give you a little insight into what is going on. In the future I will add more info to the cache screen.
Urg I need to improve the caching system. Currently the app just dumps all of the stuff it downloads into a folder and loosely organizes and manages it. If you browse a lot this can grow pretty big. The data does get cleaned out sometimes but it seems like it's not aggressive enough.