[The fact that he started with "Senator" tells Leia a good deal about where he must have come from in time. To refer to her with that, instead of her royal title or simply as a wanted rebel, narrowed it down to a small timeframe of a few years.

Her grip on the lightsaber shifts as he mentions it, but her gaze doesn't leave his face. She's no expert on how to actually use a lightsaber in battle, and hers is only something she'd obtained here, with the help of a different Galen with a thing for Kyber Crystals, but it's still important to her, and in a pinch, she could likely make do with it. But she's mostly sure Krennic won't try attacking or anything while they're in these tunnels, given the lack of space and how it would likely be a danger to him if he did try anything.]

I don't think it matters much where I obtained it.

[She could say it was, but that could also be just as damaging to admit, given the fact that lightsabers are practically synonymous with the Jedi, and associating with Jedi is damaging to any reputation. And he doesn't seem to recognize her connection to the rebellion just yet. But admitting it wasn't a family heirloom would also put Galen in danger as the one who helped her build it.]

There are plenty of lightsabers here, if you're curious. Most of them happen to be in the hands of Jedi Knights.