An opa file extension is related to Psion Series 3 PDAs and used for its object files.
There is one other file type using
the OPA file extension!
.opa - Fly! RAW image opacity map
OPA file extension - Psion OPL object
What is opa file? How to open opa files?
File type specification:
The opa file extension is associated with a range of personal digital assistants Psion Series 3 with SIBO operating system (also known as Symbian or EPOC) made by Psion PLC.
The opa file stores OPL object.
The Psion Series 3 is obsolete.
This opa file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.