As mentioned above, only in the browser Google Chrome built plugin Pepper Flash Player (or rather a shared library libpepflashplayer.so). In all other browsers based on Chromium, as in Chromium browser this plug-in is missing.
We are talking about browsers such as:
Opera - Fast, secure, easy to use browser
2. Yandex Browser:
Install Yandex Browser x64 in Linux Mint
Vivaldi - browser based on Chromium and Blink engine
4. Actually Chromium:
Official website of the Chromium browser
Installation latest version of Pepper Flash Player into Linux Mint:
sudo apt install pepperflashplugin-nonfree
If the installation program does not start. For older versions of Linux Mint will probably need an additional repository
sudo add-apt-repository -y ppa:skunk/pepper-flash
Now Flash will be available in all browsers like Chromium in Linux Mint.
But only on the condition that you have installed the shared library libpepflashplayer.so.
libpepflashplayer is installed in the system along with the Google Chrome browser. But if You haven't installed Google Chrome, you need to install this library.
To do this, run in terminal the following 3 commands:
sudo gpg --keyserver pgp.mit.edu --recv-keys 1397BC53640DB551 sudo gpg --export --armor 1397BC53640DB551 | sudo sh -c 'cat >> /usr/lib/pepperflashplugin-nonfree/pubkey-google.txt' sudo update-pepperflashplugin-nonfree --install
The result of this command will downloaded Google Chrome browser, go unpack and get library Pepper Flash Player (libpepflashplayer.so) and installed in the system for use by all browsers based on Chromium. Google Chrome itself will not install.
Also, this command updates the library libpepflashplayer.so in the system after the release of a new stable version of Google Chrome. Again, if you have installed Google Chrome in the system, then run these commands to install/update libraries is not necessary at all, it will be updated along with the updating of the Google Chrome browser.
You can now open the browser and use Flash (of course, if you have the browser opened, it should close and open again).