Take a look at unique features such as the rounded ivory keys or the tablature record of the Fantasia in C minor. In 1983 this manuscript was compared with a salary receipt that Johann Sebastian Bach had signed and it proved to be authentic.
A tablature was a common way to write down incomplex songs in the 17th and early 18th century. It is a combination of lettering (pitch) and dash symbols (tone duration). There is no standardization of tablature, therefore it may vary in each manuscript. Tablature is especially suitable for printing. Vocal works were not written with tablature. Today it is used mainly for the guitar.