This site introduces unknown Emanuel Bach (C. P. E. Bach).
ChatGPT4o writes as follows (please note that it may not be accurate):
Emanuel Bachʼs Fantasia in D Major (Wq. 117-14) is a work characterized by the free expression and brilliant character of the empfindsamer Stil. The bright key of D major imparts an open and lively atmosphere throughout the piece. It is marked by improvisational development, with unexpected harmonic changes and rhythmic flexibility creating vibrant music. Despite its brevity, the piece captivates the audience with its expressive melodies and structure. Performers are required to employ techniques that highlight the brightness and free emotional expression of this piece.