Shimano released Altus M2000 in 2017. This is an entry level groupset, so got almost no attention. But it was somewhat a milestone release: with M2000 series, even the lowest group got almost all technologies from the higher groupsets, including Hollowtech II, and Shadow (not Shadow Plus which includes clutch). It also become 9 speed.
This shifter is probably released a while later then the M2000 release, because the earliest mention of it I can track dates back to 2020.
Altus SL-M2000 is 3 speed, and unlike higher end models, not 2/3 selectable. It does have an optical indicator which is fixed, while up to XTR, higher end models offer removable optical indicators.
It’s all plastic and steel, thumb shifters look flimsy, but shifting feel is pretty good – especially for a shifter for under $20. It performs better than it looks. Weight is 126 gr’s, beats SLX models, probably on par with XT’s, but obviously not lighter than XTR’s.