The highlight for me in this release is: The racket/treelist and racket/mutable-treelist libraries provide list-like containers that support many operations in

The highlight for me in this release is: 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) [1] https://docs.racket-lang.org/reference/treelist.html#(part._treelist) https://docs.racket-lang.org/reference/treelist.html#(part._... [2] https://dl.acm.org/doi/abs/10.1145/2784731.2784739 https://dl.acm.org/doi/abs/10.1145/2784731.2784739