How do assign the user "system" to trigger all scheduled, timer triggered flows?

Thanks for adding

improve: added system user for system tasks

in https://support.onify.co/changelog/onify-hub-api-2300

But how do I use it?
I tried setting the "owner" of a flow to "System", but it doesn't reflect in
/admin/processes
as I expected, when it is triggered by timer.

Also, what does "owner" of a flow really mean? None of our flows has an owner today.
Except for the one I set to system above, and now I can't remove it as the admin GUI doesn't have the possibility to clear it, except through the api. I thought that

improve: add '-' to clear selected option for single select dropdowns

in https://support.onify.co/changelog/onify-hub-app-2124-released
but that maybe was for the workspace GUI?