This site introduces unknown Emanuel Bach (C. P. E. Bach).
ChatGPT4o writes as follows (please note that it may not be accurate):
Emanuel Bachʼs Polonaise in D Major Wq. 116-49 (H. 323) is one of the works that showcases his unique musical style. This polonaise, while possessing the rhythmic elements of a dance, richly expresses the emotional fluctuations characteristic of his music. From the outset, it has a bright and festive atmosphere that captivates the listener. In the middle section, more introspective and delicate expressions can be observed, providing a vivid contrast. Bachʼs skillful harmonic progressions and melodic development offer a fresh surprise to the audience. The improvisational elements common in his works are also felt, making it a piece that expands the expressive range for performers.