What type of law is this?
example: my court uses precedents to determine court cases. this is known

i bought a new phone

explanation:

i will send you the money when i get back from lunch

an informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.