Skype shared configuration
The configuration of Skype that is not related to a specific account is saved within shared.xml file. On *nix systems that file is located in the ~/.Skype directory. The configuration file is clearly XML based.
Much of this file, although stored in textual form, is non-the-less binary. Most notably config Lib BCM consists of subtags named _D (where D is a decimal number), and within these tags there large blocks of Hex strings (A-F are written in capitals). Other binary tags are config Lib Connection HostCache, config Lib Connection NatTracker ProbeResults *, config Lib FeatureTracker Signatures *, config Lib Griffin IP, config Lib NBwE_BandwidthStorage, config Lib NBwM_Storage, config LibPropsManager PermaProps, config Lib SD NodeTokens.
CSV is also sometimes stored in some tags, such as config Lib Connection Bandwidth InHistory and config Lib Connection Bandwidth OutHistory.
Locking is done via an empty shared.lck file that is created in the same directory as shared.xml.