I'm using Linux distros for like 10 years now and recently I (again) didn't even know how to close a window. Is it Super+W? Super+Q? Alt+F4? All of those 3 might work.
How do I access app preferences? Ctrl+Alt+P? Ctrl+Alt+O? Ctrl+Alt+S? You know, because "preferences", "options" and "settings". All those shortcuts work depending on the app.