applied by centre left and liberals
It's a term that originates with the left. Specifically, those who broke with the USSR over imperialist invasions, referring to those who did not. More broadly, it refers to the authoritarian left (as opposed to the anarchist left).
It's like a Calibri-fied version of Trebuchet. You can actually tell the difference between I and l without changing the font to check. It's an improvement.