It was actually originally announced/demoed on a Galaxy Nexus running ICS back in 2011! They might have removed it at some point after that and added it again f

It was actually originally announced/demoed on a Galaxy Nexus running ICS back in 2011! They might have removed it at some point after that and added it again for the Pixel 4 since its entire gimmick was the soli sensor https://www.theverge.com/2011/10/18/android-ice-cream-sandwich-feature-face-unlock https://www.theverge.com/2011/10/18/android-ice-cream-sandwi...