What is proot-distro?
proot-distro is a proot helper that can be used in Termux. You can install this without adding additional repositories.
What is the purpose of this project?
The purpose for this is to add older, possibly useful distros back in a form of custom sh files.
How can you add the distros you want?
Simply copy the files you downloaded to /data/data/com.termux/files/usr/etc/proot-distro and they will show up.
How do they appear as in the list?
They appear as the distro's version then the file name. The comment and installation status will be shown if you use proot-distro list --verbose.