How the lib actually works.
Two deep-dives, both teaching the genuinely interesting bits the home page can't fit. The Anatomy section gives the headline; these go under the hood.
The hidden mirror.
How the lib anchors its popover at the textarea caret — exposing the parallel <div> it uses to compute caret pixel coordinates.
What a screen reader hears.
Every ARIA attribute the combobox-as-substring contract touches, exposed live as you type. Why this lib doesn't mutate roles, doesn't own a second tab stop, doesn't shift focus.