There is only one file type that uses the .OT extension:
theWord Old Testament Text Module
File used by theWord, a free Bible reading program; stores a copy of the Old Testament in a plain text format; contains tags that markup the text so that is recognized by theWord; used for distributing digital copies of the Old Testament.
OT files are commonly distributed as ".ot.exe" executable files that self-install the Old Testament version when opened.
Updated: March 2, 2012