There are free software command line utilities, unar and lsar, that can read .rar files (including RAR5!). They were originally programmed for the macOS app The Unarchiver, but for instance, GNOME’s File Roller will also make use of them.
https://theunarchiver.com/command-line
I kinda hope someone eventually reverse engineers rar compression
7-Zip can extract .rar just fine. It does not have a .cat extractor though.
There are free software command line utilities, unar and lsar, that can read .rar files (including RAR5!). They were originally programmed for the macOS app The Unarchiver, but for instance, GNOME’s File Roller will also make use of them. https://theunarchiver.com/command-line