They are not designed for the general public, however they are created by manufacturers for use at their OEM dealerships.
Manufacturers have a team of technical engineers, writers and illustrators who compile information for these service manuals.
Some companies create aftermarket repair manuals for the general public to purchase such as Clymer Haynes[1] and Triple M FZCO.
Factory service manuals are generally the only source of information for manufacturers labor time guides.
[3] For vehicles, the following content are usually covered: body, frame & mounting, engine, suspension, driveline, brake systems, transmission/transaxle, clutch, chains, exhaust, fuel, steering, shocks, climate control, instrumentation & Warnings Systems, battery & charging systems, audio, lighting, electrical distribution, Anti Locking Braking System (ABS)[4] and wiring, as well as listing nut and bolt torque specs.