The yellow bar in iTunes

[colineve]

When my iPad is connected(and iPhone) as well as the apps and photo's bar I have a yellow bar telling me I have 3g of data in there but can anybody tell me how I can find out what this data is please

 

[scifan57]

If you're talking about the yellow bar labelled "other", it can contain the operating system, stored emails, messages, app data, etc.