Inspired by chwb
from wmutils.
This uses LuaJIT FFI to call some C functions from XCB directly to change the window's border color.
This is made to work with bspwm, but can probably work with other X11 WMs.
Requires: (You probably already have these installed)
libxcb
xcb-utils
use 'Kody-Quintana/x11-border-color.nvim'
require("x11-border-color").setup({
normal_color = "#2cba1f",
insert_color = "#e21855",
--restore_color = "#FFFFFF", -- If using bspwm, the default restore_color is the output of 'bspc config focused_border_color'
})