As spotted by Tktechnewsblog(via Phonearena), the FCC filing by Motorola, shows that the device will measure 140mm in height and 72.6mm in width, suggesting a display size of approximately 5.2-inches - in line for what's rumoured for Moto X+1. Other documents in the filing reveal Bluetooth 4.0, LTE, NFC, and Wi-Fi 802.11 a/b/g/n/ac connectivity options.
The report also speculates the listed device may be the rumoured Moto X Play, which too is anticipated to come with a 5.2-inch display as a mini-variant of the Moto S. However, the FCC certification only reveals model name 3578 and FCC ID IHDT56QA1, giving us no indication or correlation with previously leaked model names. With the publication of the FCC reports just ahead of the September 4 event however, it is more likely the device being referred to is the Moto X+1 that's anticipated to be announced at the event next week.
Previous reports had indicated Pictures), the Moto X Play, the Moto S and the much-anticipated next Nexus smartphone codenamed 'Shamu'.
( Also see: Moto X+1 was leaked online by @evleaks. The alleged Moto X+1 render showed the alleged handset with Verizon branding, tipping that the successor of the Moto X will be made available on the mobile carrier. The render further showed the handset in two versions - one Black, and the other with a wooden back.