In some mockumentary shows, like 'The Office', the mockumentary format is diegetic, because there is actually a documentary being filmed in-universe. In others, the mockumentary format is extra-diegetic, and simply a story telling device allowing us to see the thoughts of the characters, like a modern-day soliloquy; see, eg, 'Modern Family'.
In 'Parks and Rec', is there an in-universe documentary being filmed, or is it just the format of the program behind the fourth wall?