Is Blizzard teasing introduction of a new Overwatch character?

Activision Blizzard sent out a rather cryptic tweet today and quite quickly it has become a huge talking point for some gamers.

Based on the post below, you can see why people are jumping to all sorts of conclusions. Blizzard has seemingly presented an image in a way that suggests it's classified information, and their response to one inquisitive gamer only added more fuel to the fire, it would seem.

Check it out:

This archive document seems to be referring a prototype version of a "Biotic Rifle," but will the introduction of a new weapon also pave the way for the debut of a new character?

Only time will tell.

[Blizzard]