This is NOT an official Opencart release. They removed OCMOD in Opencart 4. It is a custom-made module made specifically to ease developing of projects.
OCMOD functionality for Opencart 4.x.
Install it via installer
go to User Groups and enable for administrator: extension/ocmod/modification and extension/ocmod/module/ocmod
go to Extensions / Modules and install and enable OCMOD. After enabling, click on the Modifications button next to the Save button.
Now refresh the modifications as you normally would.
A new menu "Modifications" will appear under "Extensions".
Further updates and details on this module will be based on budget.