There is only one file type that uses the .OWL extension:
OWL Source Code File
Source code written in OWL - the "Obfuscated Weird Language;" based on the Forth and FALSE programming languages; only supports integer numbers and 26 variables - A through Z.
OWL is written in C, using GNU extensions. OWL files can be run using the OWL interpreter, which can be installed on any system with gcc (the GNU Compiler Collection).
Updated: September 23, 2009