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 G Major (Wq. 117-11) is a work that exemplifies the empfindsamer Stil, characterized by its free and improvisational elements. The bright key of G major imparts a lively and approachable atmosphere throughout the piece. It is marked by a free development unconstrained by form, with harmonic changes and rhythmic flexibility that possess a unique charm. The piece demands an improvisational performance style, testing the performerʼs expressiveness and technical skill. Despite its brevity, it unfolds a musical world rich in lyricism and creativity.