There is only one file type that uses the .VALA extension:
Vala Source Code File
Developer file written in Vala, a programming language used for developing GNOME applications using the GObject system; uses a syntax similar to C# and can be compiled into C code using valac the Vala compiler.
Once compiled into C code, developers can compile the C code into an actual program that runs on the target system.
Updated: August 31, 2013