Sets the extension used by VSS to create a temporary merge file. The default is .mrg.
Merge_Ext = extension of temporary merge file
Gives all temporary merge files the extension .mrg:
Merge_Ext = .mrg
When VSS performs an automatic merge, it creates a temporary file with this extension in which to perform the merge. When the merge is complete, VSS either renames this file or deletes it; so, in general, you should never see this file. However, in case of failure during a merge, you can look for the .mrg copy of the file.