I studied mallocng a bit and wrote some notes about it: https://gist.github.com/MaskRay/ac54b26d72452ac77ac578f2e625369f Hope it can be useful to other interested readers. `git log -S something` in the https://github.com/richfelker/mallocng-draft repository helped me a lot:) Anyhow, some things are still quite unclear to me, e.g. the various counters (seq/bounces/unmap_seq) (according to the log, the parameters are largely un-tuned). It'd also nice if someone (maybe the author:)) can take some notes there and contribute to https://wiki.musl-libc.org/ or https://musl.libc.org/manual.html