The document discusses MusicXML, the standard format for sharing interactive sheet music between applications. It describes how MusicXML represents musical elements like notes, keys, clefs, and time signatures in a structured XML format. This allows different software to accurately import, export, read and write musical scores and data in a common format. The document provides examples of MusicXML code to represent a single middle C note, and explains how software can generate and parse MusicXML to work with musical scores and data.