Returns a base directory in which to access application data such as icons that is customized for a particular user.
On UNIX platforms this is determined using the mechanisms described in the XDG Base Directory Specification. In this case the directory retrieved will be `XDG_DATA_HOME`.
On Windows this is the folder to use for local (as opposed to roaming) application data. See documentation for CSIDL_LOCAL_APPDATA. Note that on Windows it thus is the same as what get_user_config_dir returns.
a string owned by GLib that must not be modified or freed. |