The latest Moto Voice app version references the Moto G6 and Moto G6 Plus, two phones which Motorola has yet to release or officially announce. While there is no doubt that the Moto G6 and Moto G6 Plus are on the way, as numerous leaks have already showcased, it's not everyday that a brand mentions unannounced products in already existing and available services, though it isn't exactly unheard of either. Also worth mentioning is that even though Motorola hasn't announced the next devices in the Moto G family just yet, it's expected to unveil the Moto G6, Moto G6 Plus, and Moto G6 Play on April 19, which is tomorrow, so referencing two of the three phones in the app that will be a big part of those devices a day ahead of time should't be a huge shock.
In addition to mentioning the Moto G6 and Moto G6 Plus the Moto Voice app also shows off a drawn version of the phone, albeit without nearly the same level of detail that you can see in previously leaked renders. That said the graphic in the app does look like those leaked renders, though not by much as it's just a simple graphic with the home button/fingerprint sensor being the only discernible detail.
The screenshot below which is from the latest version of the Moto Voice app also mentions that BETA features will be available on the 2018 Moto G6 and Moto G6 Plus. The app, while providing benefits for other Motorola devices, also seems to have been updated in part to prepare for the Moto G6 family release. While the app does mention support for new features on the two phones there is no mention of what features those will be. That makes sense given they might be new features that aren't yet available on other Motorola devices, in which case Motorola likely wouldn't want to detail them until it actually unveils the phones that they're for. With the announcement thought to be happening tomorrow more information should pop up on those features soon enough.