As you already know, Tor is a browser that helps you stay anonymous on the internet.
Whenever you download a file, Tor warns you about opening the file after it is downloaded.( you should open files offline if it is from unknown/untrusted source)
The best way is to open the file in a VM. But there is also firejail (sandboxing) that allows you to open files as safe as in a VM with right parameters.
Example : reading pdf’s from unknown/untrusted sources in okular
firejail **–net=none** –seccomp –private okular
It is not much, but i thought you should know this.
Further reading :
In cmd : man firejail