A .monitor file extension is related to the HP Printer Utility and used for its monitor plugin.
MONITOR file extension - HP Printer Utility monitor plugin
What is monitor file? How to open monitor files?
File type specification:
The monitor file extension is associated with the HP Printer Utility, a software for manage printers, developed by Hewlett-Packard for Microsoft Windows and Apple Mac.
The .monitor file contains monitor plugin.
This monitor 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.