Explore the rewrite of Bindat, an ELisp library for manipulating binary data, in this 30-minute conference talk from EmacsConf 2021. Delve into the library's evolution, including its conversion to lexical scoping, new design, and enhanced features. Learn about the BinDat specification, documentation improvements, and advantages of the rewrite. Examine practical examples and consider both positive and negative aspects of the changes. Gain insights into how this niche library, used by packages like Websocket, EMMS, and cpio-mode, was optimized for efficiency and flexibility in Emacs-28.