pip3 install mat2
When bubblewrap is installed, mat2 uses it to sandbox any external processes it invokes.
There is a package available in Debian.
We use copr (cool other packages repo) as the Mat2 Nautilus plugin depends on python3-nautilus, which isn't available yet in Fedora (but is distributed through this copr).
First you need to enable Mat2's copr:
dnf -y copr enable atenart/mat2
Then you can install both the Mat2 command and Nautilus extension:
dnf -y install mat2 mat2-nautilus
mat2 is available in the torbrowser overlay.