Type random, select the word and click ? -> About Notepad++
I recall a feature that would show a quote in a new document each time the application was opened. I'm not sure if This is the same quotes in the source.
Unfortunately I couldn't find any information about this on Google but it was documented in one of the older change logs.
Yes, it's an easter egg. Add -qn="random" to the Target in the shortcut you use to open Notepad++