I appreciate @dionys's recent assiduousness in creating tag wikis. But recently one for the system tag came through the review queue that I voted to reject. The reason was that it seemed inaccurate currently and perhaps not reflecting the focus that the community would like for the tag. The questions currently under the tag exhibit too broad a range of topics: primarily either Mathematica as a software system (system files, system options, packages, contexts, etc.) or anything called a mathematical system (usually a system of some sort of equations); plus a few oddballs. I think the lack of a good tag wiki has contributed to the incoherence. At the time I voted, I had no guide for judging how well the description captured its intended meaning. I felt it probably could have been improved, but I didn't know how.
Later I found some discussion of the issue in Do we really need that "system" tag? but it does not seem that a consensus was reached. One problem is that in my mind any question about Mathematica functionality in some way relates to the system. Defining appropriate boundaries would be difficult for me.
Can the system tag be defined appropriately? What should be included and excluded? I don't think defining it would be too controversial, but in case of disagreement, it seems the standard procedure is to post competing descriptions and vote on them.