Wayland vs X11: what is the difference?
X11 is the long-standing system that draws graphics on Linux desktops. Wayland is its modern replacement, with a simpler design and better handling of modern screens.
Why it matters when you use a bootable USB drive
Most big desktops now default to Wayland. If a program misbehaves, many systems let you pick an X11 session at the login screen.