The highlight for me in this release is:<p>The racket/treelist and racket/mutable-treelist libraries provide list-like containers that support many operations in effectively constant time, including appending and extracting sub-lists without mutating the given list. Treelists are implemented as RRB Vectors, invented by Stucki, Riompf, Ureche, and Bagwell. (see 4.16 Treelists [1] and RRB vector: a practical general purpose immutable sequence [2], ICFP 2015)<p>[1] <a href="https://docs.racket-lang.org/reference/treelist.html#(part._treelist)" rel="nofollow">https://docs.racket-lang.org/reference/treelist.html#(part._...</a><p>[2] <a href="https://dl.acm.org/doi/abs/10.1145/2784731.2784739" rel="nofollow">https://dl.acm.org/doi/abs/10.1145/2784731.2784739</a>