Motorola, or Moto as Lenovo has shortened their name now, has essentially three product lines. There's the flagship Moto X (which in 2015 morphed into two smartphones, the Moto X Play and Moto X Style), the Moto G which is a mid-range smartphone and the Moto E which is their cheapest smartphone. It actually comes in at $99 right now on Amazon. The Moto E was announced just before Mobile World Congress last year and was a pretty great smartphone, especially when you consider the price. The Moto E 4G LTE launched with a $149 price tag with the 3G model coming in at $119.99. The Moto E has a 4.5-inch qHD display, Qualcomm's Snapdragon 410 processor (ironically the same as their mid-range Moto G) that clocks in at 1.2GHz, 1GB of RAM, 8GB of storage along with a microSD card slot. Motorola had a 5-megapixel camera around back with a VGA front-facing shooter. The 3G version sported the Snapdragon 200 - the difference was due to LTE.
The Moto E 2015 wasn't the most compelling smartphone, but it sold pretty well because it was cheap but still capable. However, Motorola opted not to update the device to Marshmallow here in the United States. While it launched with Lollipop, and was updated in other regions - including China - now we have the kernel source for that update. Before users in the US of the Moto E 2015 get too excited, it's worth pointing out that while the kernel source is available, ROM developers don't have necessarily everything to make a stable ROM for the Moto E 2015. But this is a big step for developers to play around with. The source information is located on GitHub for anyone thinking of playing around with the kernel source code.
We're about due for another Moto E, seeing as last years was announced on February 25th. The Moto E 2015 is now over a year old. Motorola did say that both the Moto E and Moto G weren't going away, so perhaps there will be a successor pretty soon. The kernel source being open sourced isn't a big deal for most users, but those waiting to flash a custom ROM based off of Marshmallow are going to be pretty excited for this. And we should see some stable ROMs popping up soon.