This is the core scripts within the calendar system, and is what most users would want to clone after downloading the initial calendar software.
Since the system uses other git repos as submodules, you will want to clone via:
git clone --recursive https://github.com/jskenney/calendar-core.git
See the calendar repo for additional information
Within the calendar-core directory, run the following command to update the calendar core
git submodule update --recursive --remote
git pull --recurse-submodules
If you keep your class notes within a git repo, you will need to add this as a submodule
git submodule add -b master https://github.com/jskenney/calendar-core.git
git submodule init
git submodule update --init --recursive
git submodule update --remote