ConstContext entry for indicating the type of source annotation.
Context entry containing the link filters applied on link queues within the context scope. Setting this entry too high in the context hierarchy could result in too much being filtered out.
When adding entries to this file, also add a shortcut for them in the contextKeyShortcuts TSDoc comment in ActorIniQueryBase in @comunica/actor-init-query if it makes sense to use this entry externally. Also, add this shortcut to IQueryContextCommon in @comunica/types.