Strings like "\<BS>" are a feature of vim script, so they don't work in Lua (or fennel which compiles to Lua). The vim api provides a function to convert them called nvim_replace_termcodes. You can use it like this in Lua: vim.g.maplocalleader = vim.api.nvim_replace_termcodes('<BS>', true, true, true). It should be easy to translate that to fennel.

w00t! That did it, thanks!

Some people are, https://github.com/rafaeldelboni/nvim-fennel-lsp-conjure-as-clojure-ide is a good place to start.

That's exactly what I was customizing... Gotta have <BS> as maplocalleader 🙂