This is an unfinished model of the Stridsvagn 74 Light Tank. Originally (before the game’s alpha release), the Strv 74 was supposed to be one of low Tier vehicles of the third dealer before it was decided to build his portfolio mainly around Chinese vehicles.
In the original design, the Strv 74 was supposed to be preceded by the Type 62 Light Tank and followed by the Type 63 Light Tank (a Chinese answer to the PT-76). This was due to the fact that all vehicles were originally assigned their Tiers based on their age instead of armament, armor and mobility. Upon review, this design made very little sense, potentially placing a vehicle with a low-power 75mm gun as high as Tier 4. That is why it was dropped in favor of the current Zhang Feng’s layout.
This tank would periodically appear in various design documents during the first years of Armored Warfare but the full rebalance of vehicles that took place in 2017 made it unsuitable for introduction as it was generally not powerful enough to appear even on Tier 1.