The latest version as of 10th November 2020.
What does not
Could not browse to the Firefox cache folder because it is in a hidden directory. Using the textbox to enter the path manually didn't work.
By default, the cache folder for Firefox on Linux is in ~/.cache.
MZCacheView doesn't appear to be able to browse hidden folders (at least in my case), so instead create a symlink from your cache folder to something like ~/mozcache, and then select that as the folder.
I suspect this is not a problem if you're running the Windows version of Firefox in WINE.
Find the location of your cache folder by going to about:cache in Firefox.
What was not tested
|Linux Mint 20 "Ulyana"
|Nov 10 2020