.BA_ File Extension
What is a BA_ file?
Renamed .BAT executable file that uses an underscore ("_") instead of the "t" so that the file cannot be accidentally run when double-clicked in Windows; can be renamed back to a ".bat" file and then run.
BA_ files are also used by some application installers so that the user doesn't run the file instead of an intended and more obvious installer file such as Setup.exe.
NOTE: A BA_ file may also be a compressed BAT file that can be expanded using Microsoft's Expand command line utility. This file type uses the underscore convention in the same manner as .EX_ and .DL_ files.