There is only one file type that uses the .MSHA extension:
Microsoft Help Asset File
File used by MS Help Viewer 1.x, a Visual Studio component that helps developers author help documentation for software applications; saves the help manifest, which defines the help "Books" (help documents), which contain "Packages" (.MSHC help content files) to be installed.
MSHA files are saved in an XML format and can be authored with any text editor. The MS Help Viewer 1.x standard requires that they use the filename HelpContentSetup.MSHA.
NOTE: The MS Help Viewer 1.x format replaces the MS Help 2.x (.HXS) and Help 1.x (.CHM) formats.
HelpContentSetup.MSHA - The filename required by the Microsoft Help Viewer 1.x standard.
Updated: March 5, 2012