Show characters inside a box
https://www.ctan.org/pkg/showcharinbox
Vafa Khalighi, who was maintaining showcharinbox, handed maintenance to this bidi-tex GitHub Group (which initially consists of members of the LaTeX3 team).
Issues may be entered here.
If it proves necessary to update the files, this repository will be filled with files retrieved from CTAN:
http://mirrors.ctan.org/macros/latex/contrib/showcharinbox.zip