These files are synced between all Calendar/Reminders source repositories automatically using git subtree.

That means that any changes you make here do not only impact this project.  They impact all projects.
If that is what you intend, go ahead.

The source of truth for these files lives at ssh://git@stash.sd.apple.com/ccrinternal/CalendarSharedConfigurations.git
If you are not working in that project and you want to make changes that will only affect your project, then make sure your
changes are not inside this directory.