There is only one file type that uses the .OVX extension:
Object-based Visual Application Language File
An OVX file is a data file used to develop applications for Psion devices, such as Netpad, Workabout, and MC 400. It contains Object-based Visual Application Language (OVAL), which is a programming language similar to Visual Basic. OVX files are no longer used since Psion computers have been discontinued.
OVAL was specially designed to build Psion apps and closely resembles the Visual Basic 3 programming language. However, Psion was purchased by Motorola in 2012 and its devices were discontinued. OVAL is no longer supported.
NOTE: A Windows IDE named "OVAL" supported OVX files but it is no longer available.
Updated: February 14, 2017