Not used in any modern ap's that i know of, and only used in some models back in the day.
Think our hood tachs are one example. Some side markers and instrument clusters on Buicks and Caddys, etc.
Parts storse can order thier own brand. Just tell them 168 "clear" bulbs.
Also any GM dealer. Part # is 9425542.
Come per 10 in box. $1.32 ea, so $13.20 plus tax.