If I upload / download any file to/from Gmail is it traceable using Windows logs? What information is exactly stored in Windows logs regarding net browsing?
Windows is an OS and its logs concern the OS-level of activity.
Browsing the Internet is an application-level activity, not an OS activity, so there will not be OS logs on this activity.
If you want to know what can be logged, you could simply look at the lists of Windows event IDs.