The code appears to be a specific identifier, possibly for a community-made patch, a data-mining leak, or a private modification related to Splatoon 3 .
Detailed official patch notes can be found on the Nintendo Support Update History page.
The "NSPRAR" (Neural Systems Patch for Robust Adaptive Response) focus in this update seems to be on leveling the playing field for mid-range shooters and brushes.
Expect a rebalancing of the and Splattershot Nova (damage drop-off reduced). Meanwhile, Tri-Stringers may receive a charge-hold buff after community outcry over their low pick rate in X Rank.
It sounds like you’re referencing a update (potentially version 9.2.0 given the “920” part) and the word “nsprar” — which might be a typo or shorthand for NSP/RAR (Nintendo Switch Package / archive format), or something else like a codename or scrambled text.