Hi thanks for answering...
From what I can tell, the license for Mathematica is tied to the Raspberry Pi hardware (see section: Permitted Uses and Installations), not to a particular type of operating system. Of course, what‘s officially supported is a different matter.
Both Raspberry Pi OS and Kali are based on Debian, although Kali has a rolling release policy, so it‘s always considerably more up to date (which is the main reason why I like it, aside from a slicker looking UI, and some nifty network/sysadmin security testing tools).
If you have a 64-bit or 32-bit version of Mathematica is fairly easy to establish, look at the output of this:
$ file /opt/Wolfram/WolframEngine/12.1/SystemFiles/Kernel/Binaries/*/*
/opt/Wolfram/WolframEngine/12.1/SystemFiles/Kernel/Binaries/Linux-ARM/ELProver: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux 3.2.0, BuildID[sha1]=e380f960723d748626a08893fa06331715488d51, stripped
/opt/Wolfram/WolframEngine/12.1/SystemFiles/Kernel/Binaries/Linux-ARM/WolframKernel: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux 3.2.0, BuildID[sha1]=c0beadca4282b84bf648e231fd2d1e99c628170d, stripped
My results clearly show 32-bit executables, so even without having access to the install logs or whatever, it‘s pretty easy to see what‘s installed. In case you should have a newer version of Mathematica, like e.g. some sort of 12.2 beta or something, the path would differ in easily discoverable ways.
Being a 32-bit executable aside, Mathematica works just fine after jumping through the hoops described here Installing Mathematica under 64-bit Kali Linux on a Raspberry Pi
Haven’t been able to test how much memory it can access, though...