LG officially revealed its new 'Wing' smartphone in a livestream earlier today, following weeks of leaked videos and several teasers. The pre-recorded event was over an hour in length, so it's not too surprising that a teaser for a new slide-out device at the very end went unnoticed by most people.
The end of the livestream shows off an animation of what looks like a phone sliding outwards. There's very little detail visible, so it's not clear if the section sliding out is a keyboard (perhaps for people mourning the death of TCL's BlackBerry-branded phones), a covered display, or something else entirely. I'm guessing an Xperia Play-style gamepad is off the table, given there's very little clearance between the sliding component and the outer shell.
The teaser brings back memories of the LG G5, which had a removable chin for accessing the battery compartment and attaching 'Friends' modules. LG said during the Wing's unveiling that it was developing several other phones under the 'Explorer Project' banner, so perhaps the slide-out device will be the next to market.