Documentation
System-wide settings
System-wide settings help to configure systems where most components share the same collections.
Selecting a collection for the whole system means that every system that has the inherit checkbox enabled uses this collection. For example, if every page of the website must have a google analytics integration just check the system-wide collection and inherit.
The inheritance mechanism automatically activates the collection for every component. It is not possible to overwrite it unless the inherit box is disabled.