I'm using a great addon called "Cycle Cameras" made by @CoDEmanX for Blender 2.79b which I'd like to use in Blender 2.8x as well.
Fortunately there already is an updated version by @Matthias & @batFINGER. However, I can't get it to work properly. Everytime I try to install it via User Preferences > Install from File the addon doesn't show up in the list. I tried to install it in Blender v2.80 and v2.81 without any success.
What am I doing wrong? How to install the updated version properly?