[Coldbox 7.2.1] folder system.async.cbproxies missing

I’ve had to install the latest Coldbox version on a system (that is behind a firewall and has no outside connection to the internet and also no CommandBox installed). I’ve downloaded the zip file from GitHub - ColdBox/coldbox-platform at v7.2.1.
When starting up my Coldbox app, I always got an error from the coldbox bootstrap process that coldbox.system.async.cbproxies.models.Optional has not been found.
Actually the whole folder “system.async.cbproxies” IS missing in the github repo.

Then I’ve installed CommandBox on my local machine and did a “install coldbox”. After that command; the folder “system.async.cbproxies” is there…

I am missing something? Why is the folder cbproxies not in the github repo, but it’s there when I install Coldbox with CommandBox?