Derived from the pattern of a scene's presence and absence across the six systems, not from a view about the music. A scene that appears in the behaviour-built systems but not in the citation-gated one is in a materially different position from one that appears only in a marketplace's vocabulary, and the difference is checkable.
The consensus scene
Present in every system that maintains a rap vocabulary.
Example. G-funk, grime, boom bap, trap
The scene is old enough, distinct enough and commercially large enough that behaviour-driven, editor-driven and retail-driven systems all had to name it. Consensus is a lagging indicator: it means the argument is over.
The scene ahead of the press
Present in the behaviour and community systems, absent from Wikipedia.
Example. sexy drill, jersey drill
Listeners and taggers are tracking something the citation-gated system cannot admit yet, because Wikipedia requires published sources and the publications have not caught up. This is where the front edge actually is.
The press label
Present ONLY on Wikipedia. No data system recognises it.
Example. mumble rap
A critical term applied from outside rather than a scene label used from inside. Systems built from artist and listener behaviour never adopted it because nobody was ever behaving it. It survives because journalism keeps citing journalism.
The retail fossil
Present ONLY on Discogs, often with a huge corpus attached.
Example. thug rap, at 23,916 releases
A category that describes how a record was SOLD rather than how it sounded, frozen around the physical-media era because a marketplace's vocabulary optimises for shelving. Larger than Horrorcore and Cloud Rap combined, and invisible everywhere else.
The boundary object
Present everywhere, filed incompatibly.
Example. grime
Wikipedia files it as a DERIVED genre rather than a subgenre, which is an explicit editorial ruling that it is not hip-hop. MusicBrainz lists it flat alongside rap genres. Every Noise puts seven grime variants inside the rap cluster. The question has already been answered three incompatible ways.
The micro-scene
Present in the fast community systems only, absent from the slow ones and from retail.
Example. plugg, sigilkore, digicore
Internet-native, timestamped, and legible mainly to the systems that let anyone add a tag. These leave the clearest documentary trail of any scene in history and the least institutional recognition.