How to close evince Document Viewer (PDF)

Usability problem, End User perspective:

Having opened an PDF in evince Document Viewer (Ubuntu 20.04 LTS), how to close via UI?

• there is no close button.
• even if you go fullscreen by pressing F11, the menu at right top does not have a "close" function, nor the top menu
• ESC doesn't do the job (which would be the most expected way)
• Q doesn't work either
• nor does CTRL-Q, Shift-Q, CTRL-Shift-Q
• nor F4 or Alt-F4

That's all the key combinations people are used to for closing a window or program.

So, what can I tell the average end-user about this? Guiding them through opening a shell, identifying the process and killing it doesn't instill confidence in ease of use of Ubuntu as a desktop.

In my Ubuntu 20.04.3 LTS the Document Viewer alias evince can be closed

• with the x button at the top right corner of the window or
• with the alt+F4 keys (sometimes Fn+alt+F4) or
• with the ctrl+w keys (thanks @totalynotanoob) or
• via a pop-up menu when right-clicking on the title bar.