The agency has chosen not to adopt the remaining portions of the NPRM, including a proposal which would have allowed manufactures of hybrid and electric vehicles (HEVs) to install a number of driver-selectable pedestrian alert sounds in each HEV they manufacture.
I’ve said adoption of EVs by that crowd will only come when they start slapping very loud and aggressive VESS options onto them
The hardware is already there, someone just needs to mod/hack that in.
In fact, it looks like we were going to get custom sound effects but the DOT killed it:
https://www.federalregister.gov/documents/2022/07/13/2022-14733/federal-motor-vehicle-safety-standards-minimum-sound-requirements-for-hybrid-and-electric-vehicles