There is an interesting documentary by BBC Four called The Magic of Mushrooms that shows that mushrooms are constantly releasing spores into the air.
Thank you very much for your answer! Using your advice, I successfully installed the VLC media player 2.2.2 Weatherwax on Linux Mint 18.3 running form a Live USB. Then, I just downloaded both Powder Player and Powder Web, extracted the folders from the downloaded archives for Linux in the "Downloads" folder and it worked to start Powder and PowderWeb by just clicking on these files!
Now I am enjoying the documentaries from VideoNeat.com streaming from magnet links on my PC and on my local network to a TV equipped with Chromecast 3 :)