This page documents a Wikidata policy. It is a widely accepted standard that all editors should normally follow. All changes made to it (except for minor edits such as fixing typos) should reflect consensus. When in doubt, discuss your idea on the project chat.
This page in a nutshell:
Use common sense.
This page contains Wikidata's policy on using common sense.
This policy is simple: use common sense. This policy applies to everything on Wikidata, including editing, interactions with other editors and interpreting other policies. If another policy or guideline prevents a useful contribution to Wikidata, use common sense and ignore it.