Diagram : "provided-by" meaning

Hello everyone,
I managed to create some customized viewpoints using Capella Studio by imitating the BasicVP code and this video
However, now that I want to go a bit deeper about the creation of VP, several questions come up.
The first one is : What is the meaning of “domain-context: price.data.PartPrice provided-by query “<%getPriceObjects()%>”” that is written in the Basic Price vp ( price.vpdsl/model/price.diagram.text ), and what is the difference with the “provided-by association external emde.ExtensibleElement.ownedExtensions” defined in the video ?
Any help will be appreciated !

Actually I think it will be simpler to give my whole problematic instead of multiple questions which will occur one by one.
I want to create a Viewpoint to show some properties on my system. I want to extend each physical components in order to gave them the attributes “mass ( Double ) " and " isPropellant ( Boolean )”.
This part is manageable following the exemple of the previous video.
However, I want to add two other things :
The first one is a calculation of global mass for “higher” components (ie, components with no parent component), which will be the sum of the mass of all its sub_components. I also want to add an attribute ( the integer Stage ) here.
Then, a “global” container, that sums up the total mass of the system and perform a little calculation ( sum the total mass, ponderated by the stage defined previously ) and display the result.
I think the part that I understand the less is the ‘Service’ one, the one where the calculations will be made.
I see that in the two exemples the way the two are managed seems very different ( in ‘cost.design’ for the video, and in capella.vp.price\vp/srv/org/polarsys/Capellavp/price for the BasicPrice VP). What are the functions that are generated automatically when generating the VP, and where can I modified (or create ) them ?