Static Resources and Visual Force Pages
Note that these are not "resources" in the sense that your salespeople or delivery trucks are "resources." Static Resources are Salesforce records that developers can use to extend the way DayBack behaves.
DayBack started including this before we introduced App Actions, and many things you'd do with static resources can now be done in actions, but static resources still have a role to play in some customizations. Notably, they're used when embedding DayBack on a record's page to show just the events for a particular account.
There's a pub/sub model here, so that we can publish JS events from DayBack to the VF page and have them run there. It's very much like calling a FM script from DayBack. The "script" that you want to call needs to be set up as a subscription in the static resource. We use a custom static resource sometimes if the customer wants custom navigation, e.g. we replace the static resource's navigation methods so the SF page opens in a new tab, for example.
You can't edit the stock Static Resource that comes with the package, but you can replace it and then enter its name in the custom setting. There is then a simple Apex class that runs when the VF page loads and looks at that custom setting and will load the alternate static resource, instead of the stock one, if specified. If you want to specify URL parameters, then you do this in the static resource as well. Since DayBack is in a special iFrame, you can't specify the parameters in the iFrame URL and need to set them in the static resource and then they're "published" to DayBack and applied.
Old version of DayBack also didn't have the modal methods set up in the static resource, so back in the day, if you wanted to add those, you would need to follow this path. You can see this in the old instructions in the below blog post, that have since been updated since these methods were added to the stock static resource:
That page has a nice description of how these resources actually work.