Teams & divisions
How teams are composed & different departments
How the organization divides itself into teams, and how those teams relate to each other, is often less obvious than the org chart suggests.
Every organization has a formal structure and an informal one. The formal structure is what appears in the org chart. The informal one is how work actually gets done: which teams collaborate closely, which ones rarely talk, who the connectors are, and where the real decision-making happens. New people need to understand both.
Teams change faster than documentation tends to keep up. People move, responsibilities shift, new teams form around new problems, and old divisions dissolve or merge. A record of the current structure matters, but so does a brief account of how the structure got to where it is, since that context shapes how people behave.
This is also where it is worth capturing the purpose and scope of each team, not just their names, because team names rarely tell anyone what the team is actually for.