There are a couple of chords which have similar notes.
-7b5, -6 for example.

But what do I call the chord which is (more or less)
equivalent to a C-6, but with Eb as the root note?

The key is Bb (I'm pretty sure).

Any extra theory with the answer would be appreciated, even
if only partially understood


Finally, I have found a cool signature with sufficiently dry humor.