There hasnt been any detailed information related to this parameter released in any of the jabber for windows document.
here is the link for the release notes of jabber for windows 9.7,
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/Windows/9_7/JABW_BK_CF8F083D_00_cisco-jabber-for-windows-97/JABW_BK_CF8F083D_00_cisco-jabber-for-windows-97_chapter_00.html#JABW_RF_OFFE6AE4_00
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/Windows/9_7/JABW_BK_C4C679C9_00_cisco-jabber-for-windows-97/JABW_BK_C4C679C9_00_cisco-jabber-for-windows-97_chapter_0101.html
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/Windows/9_7/JABW_BK_C4D2F1D0_00_cisco-jabber-for-windows-97.html