math mode - Xparse k argument to parse options at end of environment - TeX - LaTeX Stack Exchange
LaTeX 3 Paper | PDF
The xparse package Document command parser
macros - Can you make boolean expressions in xparse? - TeX - LaTeX Stack Exchange
LaTeX warning: "xparse/redefine-command" -- I don't care :) · Issue #183 · latex3/fontspec · GitHub
LATEX3 News
expansion - Why does xparse manual talk people into thinking that reliable expandable checking for optional arguments is possible? - TeX - LaTeX Stack Exchange