I often see questions where a user is interested not in copying a game as a whole but in pulling apart a particular game mechanic in order to better understand how it works and apply this to their own development.
In these cases questions can tend towards being subjective if a user is asking "How can I make a game like Diablo 3?" and doesn't meet our FAQ criteria. However if the user is trying to understand how a specific mechanic works more directly such as "How does a character sheet store and implement character stats for use in skills and items such as Diablo 3?" then we can apply a "Reverse-Engineering" tag (if there is something similar I was unable to find it.)
This means the question promotes non subjective discussion about how to create a mechanic. The tag allows the asker to show that they are trying to pull apart an existing example from a known game but showing any viewers they understand not to ask "How can I make X game?".
Unlike Arqade we do not use tags for labelling a particular game (for example "Diablo-3") but we should be encouraging people to try and pull apart how existing games were made so they can reverse engineer for their own benefit and learning.
This is why I believe a reverse-engineering tag or similar would work well for these situations.