A drill file extension is related to the DROPS simulator operation data format.
DRILL file extension - DROPS simulator operation data
What is drill file? How to open drill files?
File type specification:
The drill file extension is associated with the DROPS simulator.
The .drill files contain all relevant operating parameters and other data for the particular section.
Seems to be obsolete format.
This drill 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.