for the range \x2300-\x23FF; the representative glyph is \x2331, "dimension origin".
This begs the question: what should be done with the private use area, which has no assigned characters? This.
So when I first saw this character I was like "whoa. what the heck is that supposed to be?" It looked kinda familiar. So I asked my mother to bring home a particular book: On Beyond Zebra, a book by Dr. Seuss which makes up a few rather fanciful characters.
Here's a scan of one of the two index pages for On Beyond Zebra:
The glyph is, indeed, Wum. Kind of appropriate, really.
So, on beyond Zebra!
Discover new letters!
Like WUM is for Wumbus,
My high-spouting whale who lives high on a hill
And who never comes down 'til it's time to refill.
So on beyond Z! It's high time you were shown
That you really don't know all there is to be known.