Though it's a given that Sony will announce the leaked PlayStation 4 Slim and highly anticipated PlayStation 4 Neo at their upcoming PlayStation event this September 7, audience's could witness a third hardware announcement for a new handheld console as well.
As pointed out by NeoGAF, a Foxconn worker who presumably worked on assembly lines in June – the same that leaked the PlayStation 4 Slim – noted that there was a portable device being manufactured alongside it, describing it as a "PSP-like" machine.
Though this could be the Nintendo NX, it would be highly unlikely that Nintendo would be manufacturing its console so far in advance, as its prospective release date is March 2017. Furthermore, NX leaks reveal that the portable component to the console has more of a tablet-like look.
To add further speculation, Japanese blog Hakanko has reported that Sony has registered two wireless modules with the United States' FCC, both of which (AW-CB262 and J20H091) each respectively correspond with modules in the PlayStation 4 and PlayStation Vita.
Whether or not this new handheld is a successor to the Vita, a revision, or the Nintendo NX remains to be seen until early September. Luckily, fans have plenty of other leaks to keep them occupied.