What exactly is going on in chrome://histograms/? Also does anyone know what chrome://tracing/ or chrome://sessions/ do? chrome://sync-internals/ is pretty in

What exactly is going on in chrome://histograms/? Also does anyone know what chrome://tracing/ or chrome://sessions/ do? chrome://sync-internals/ is pretty interesting. I've been wanting a way to get more info on how and when everything is being synced.