Hmm, pb's right in that it's not formal MQ language - GenEd is a UNSW term... However, it's totally different. If it says that in a unit description, it is what it says; it's a unit that isn't as isn't as in depth in your major, which students outside of your major might enjoy.
For example, if you were doing MATH100: History of Maths, that would be a general education unit. People who aren't doing maths might still enjoy it, and it gives all students (including maths students) a general education, so to speak.
Ack, I hate hypotheticals... Ah, CHN112: Chinese Calligraphy is a good example. It's general, but will also help students doing Chinese, although no Chinese is required.
So yeah, 'general education' isn't an official term, like it is in UNSW, so don't treat it as one.