A report from December claimed the LG G5 would include a "Magic Slot" hardware expansion port. A leaked image appears to show the new feature in action with a bulky module attached to the smartphone.

Long before the iPhone, Apple tried to position itself as top dog in the mobile world when it released its first PDA, the Newton, in 1993. When the device was announced, it was applauded for its design, features and stylus, but its $700 price and unreliable handwriting recognition software allowed another company to force Apple out of the PDA (personal digital assistant) business when Steve Jobs returned to the company and cancelled the Newton platform and devices.

The Palm Pilot 1000 and Pilot 5000 went on sale in March 1996, and Palm's Graffiti handwriting recognition software was more accurate than Apple's Newton. The devices sold for $299 and $399 and allowed users to upgrade the RAM by purchasing a module from Palm. The original inventors of the Palm Pilot started their own company, Handspring, which sold Palm OS-based PDAs and built upon the ability to upgrade and add features to its handhelds via a "Springboard Expansion Slot." MP3, GPS and digital camera Springboards were released, but the most important turned out to be one that transformed the PDA into a smartphone.

Handspring released a Springboard module in 2000, the VisorPhone, which magically turned the PDA into a smartphone and was the precursor to the hugely-popular Treo smartphone series from Palm.

In December, we reported that LG was planning to introduce a similar expansion slot to the LG G5, called "Magic Slot," and described as a way to allow users to add hardware modules to the upcoming smartphone in order to expand its features.

While we have covered numerous LG G5 leaks since then, the "Magic Slot" feature seemed to disappear — until now. Android Authority has posted an image of the LG G5 with a "Magic Slot" module attached to the smartphone. As you can see in the above image, the module is bulky and is inserted on the bottom of the handset. It's unknown what this module actually does, but could be an extended battery, although the source points out that the module includes a dial and several buttons.

Luckily, LG will announce the LG G5 in a few days on Feb. 21, and we should hear all of the "Magic Slot" details and features at the event. As always, we'll keep you posted on any new details as they become available.