A Moto device with the model number XT1755 has hit the FCC recently, and although the device is not referred to by a codename or an official name that's to be used for the device once it launches, this isn't the first device with a similar model number to show up at the U.S. regulatory office in document filings. In the FCC documents for the Moto XT1755 there isn't a whole lot of detail that can be picked up but the FCC label location does show the general shape of a smartphone that seems to carry at least one similar design trait of Lenovo's more recent Moto devices, which is the big camera sensor on the back. In the FCC label location document you can see a larger circular shaped section towards the top which resembles the size and shape of the rear-facing camera modules on devices like the recently released Moto G5 and Moto G5 Plus.
On a diagram of the label itself, you can see the model number listed as XT1755, which would make this a variant of the XT1750 that showed up last month, and it also lists "16GB" which likely signifies that it has 16GB of internal storage. When the XT1750 showed up at the FCC last month, the same label could be seen for that particular device only it listed "8GB" instead, which again would likely suggest its internal storage amount which could be 8GB.
About a week after the XT1750 passed through the FCC some of the specifications were leaked and it was noted that the device had a 5-inch LCD screen with a resolution of 854 x 480, which could very well point to the device being the latest version of the Moto E, which is the entry level device series that sits below the Moto G series of devices. It was also listed as having 1GB of RAM, which would again be fitting of a Moto E type of device. If this is the case, then the XT1755 could be an additional version of the new Moto E with more internal storage for those that need it. It's been a while since a new Moto E was released, so perhaps Lenovo and the Moto team are due for a couple of new additions to the franchise of phones.