Try:

{nav name=C124}

To produce:

C124

This is approximately explained in the documentation?

We could conceivably special-case this since setting an empty attribute to a value isn't meaningful, I suppose.

It's an off-case for sure. We have a ton of data identifiers which all end with an equals-sign and a couple letters/numbers, which we abbreviate when referring to the datasets. I was actually trying to render the equals sign as part of the nav sequence and not just C124.

Oh, right. That works, but I think isn't documented:

{nav name="=C124"}

Produces:

=C124

And you can technically:

{nav name="name=\{nav name=\"C124\"\}"}

...to produce:

name={nav name="C124"}

...and such.

Ohhh nice, thank you I missed that
=C124