It’s here (in your beta copy of Photoshop, same as Generative Fill), and it works pretty much exactly as I think you’d expect: drag out crop handles, then optionally specify what you want placed into the expanded region.

In addition:

Today, we’re excited to announce that Firefly-powered features in Photoshop (beta) will now support text prompts in 100+ languages — enabling users around the world to bring their creative vision to life with text prompts in the language they prefer.