Since this is using the GLib functions:

data:

On Windows it follows XDG Base Directory Specification if XDG_DATA_HOME is defined. If XDG_DATA_HOME is undefined, the folder to use for local (as opposed to roaming) application data is used instead. See the documentation for FOLDERID_LocalAppData. Note that in this case on Windows it will be the same as what g_get_user_config_dir() returns.

config:

On Windows it follows XDG Base Directory Specification if XDG_CONFIG_HOME is defined. If XDG_CONFIG_HOME is undefined, the folder to use for local (as opposed to roaming) application data is used instead. See the documentation for FOLDERID_LocalAppData. Note that in this case on Windows it will be the same as what g_get_user_data_dir() returns.

cache:

On Windows it follows XDG Base Directory Specification if XDG_CACHE_HOME is defined. If XDG_CACHE_HOME is undefined, the directory that serves as a common repository for temporary Internet files is used instead. A typical path is C:\Documents and Settings\username\Local Settings\Temporary Internet Files. See the documentation for FOLDERID_InternetCache.

which all seem reasonable?