About Element Templates[]
For each Element, there is a template that can be called with another element as parameter, to get the result of their reaction.
Examples: {{Acid|Bomb}}, {{Acid|Acid}}
The data for the examples would be in Template:Acid. However, with the addition of new elements, the data would become incomplete; however, the old templates then ask the "new element" for the new data, until someone updates them.
So assume Newelementium gets introduced, then somebody needs to make Template:Newelementium listing all reaction results, like the other templates do, and then using {{Acid|Newelementium}} would result in Template:Acid calling up {{Newelementium|Acid}} to arrive at the result.
For a list of all element templates see Category:Powder Game element templates.