Library author here. I would love if people took it for a spin and gave me feedback. Also contributions are welcome, I'm currently trying to figure out ways of testing deeper into the library.
https://www.gnu.org/software/bash/manual/html_node/Readline-...
One thing I underestimated was the importance of having all readline key bindings available. People are really sensitive when certain functionality that they are used to is missing. (And you've no idea how much functionality there is in readline until you have to implement it.)