What are the “unique magic abilities” that draconians get instead of a breath weapon?

I like dragonborn, but I don’t really like the breath weapon that much. You can’t use it very often, and it doesn’t seem to scale very well at all, so it’s hard to imagine it having much relevance to a character after the first few levels. (And since I’m looking to play a warlock, eldritch blast says “why bother?”)

But I note a sidebar on page 34 of Player’s Handbook (or this section of the basic rules) about the draconians of Dragonlance, and it includes this tempting note:

In place of their draconic breath weapons, [draconians] have unique magical abilities.

What are those abilities? Where are they detailed? Certainly doesn’t seem to be in Player’s Handbook.