We need to decide what to do with a potential set of epsilon symbols with a default epsilon always being present, then dont care symbol, and how do we want to define marker epsilon symbols for strings in Mata.

Debugging constants leaking out:

Me neither. I think this is some debug value from when we were implementing this leaking out. It should be a special marker (epsilon) symbol as used in transducers, for example in noodlification, but never standardized as a special epsilon symbol. Hence, it was only for debugging back then.

Originally posted by @Adda0 in #501 (comment)