An oby file extension is related to the EPOC ROM image format. Probably obsolete.
OBY file extension - EPOC ROM image
What is oby file? How to open oby files?
File type specification:
The oby files (also referred to as Obey files) are text files containing statements that are used to control the operation of the ROM building tools.
Most likely some old format without support. No further information could be found.
This oby 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.