A datasheet is a document summarizing the performance and other characteristics of a component (e.g. an electronic component) a sub-system (e.g. a power supply) or software in sufficient detail to be used by a design engineer to design the component into a system.
Typically a datasheet is created by system manufacturer and begins with an introductory page describing the rest of the document, followed by listings of specific components, with further information on the connectivity of the devices.
In cases where there is relevant source code to include it is usually attached near the end of the document or separated into another file.