There is only one file type that uses the .UMD extension:
Splinter Cell Blacklist Game Data File
Compressed file created for Splinter Cell Blacklist, a third-person shooter stealth adventure game; contains game configuration data, such as object textures, referenced by the game for each level in Splinter Cell; not meant to be opened.
NOTE: Both UMD files and .ASS files contain gameplay data accessed by Splinter Cell Blacklist.
|Ubisoft Splinter Cell Blacklist||Paid|
Updated: August 15, 2013