There is only one file type that uses the .XMAP extension:
XMind 2007/2008 Workbook
Workbook created by XMind, a mind mapping application; created by the 2007 and 2008 releases of the software, but can still be opened by recent XMind versions; used for visually storing ideas captured during brainstorming sessions.
XMind now uses the .XMIND file extension.
Updated: June 21, 2016