Well, although usually it's a good idea to read the original post first, in this instance the original post is at best misleading because it refers to Plasma as an "operating system" rather than a desktop environment.
(Or for those who want to use even more precise terminology: its full name is either "Plasma Desktop" or "KDE Plasma Desktop", because KDE also has some non-desktop environments such as Plasma Mobile and Plasma Bigscreen... none of which are as popular as Plasma Desktop, though, so usually Plasma Desktop is colloquially called just "Plasma".)
Well, although usually it's a good idea to read the original post first, in this instance the original post is at best misleading because it refers to Plasma as an "operating system" rather than a desktop environment.
(Or for those who want to use even more precise terminology: its full name is either "Plasma Desktop" or "KDE Plasma Desktop", because KDE also has some non-desktop environments such as Plasma Mobile and Plasma Bigscreen... none of which are as popular as Plasma Desktop, though, so usually Plasma Desktop is colloquially called just "Plasma".)