This is the format string that is applied to all summaries' text in the footer. The default is "{0} = {1}" where {0} is the summary name and {1} is the value. Beware that using a formatting specific to a particular type here can cause an exception when other types use this formatting. This can be overriden on a column setting or a summary setting.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2