It is possible that "An-990" is a typo or a fictional/video game designation (e.g., from Kerbal Space Program , SimplePlanes , or similar sandbox games).
The single greatest operational hurdle for the An-225 was loading cargo from the nose. The An-990’s conceptual "best feature" was a allowing the aircraft to "kneel" and lower the cargo floor to standard truck height (1.2 meters). The nose door would slide over the cockpit, not hinge up, allowing a straight, 8-meter-wide tunnel for cargo. antonov an990 best
Below is a draft paper covering its simulated "best" features and technical context. It is possible that "An-990" is a typo