@wtremmel It does, here's the data sheet: https://sensirion.com/media/documents/48C4B7FB/66E05452/CD_DS_SCD4x_Datasheet_D1.pdf
I also own an Aranet4, and in my comparison, the SCD40 was usually within 50 ppm of the Aranet4. Definitely accurate enough to help breathing humans with their risk assessment.