TIL that there are not only -webkit-css3 properties without a modern prefixless version, but they're supported in Firefox. -webkit-text-stroke is one of them, predating even Chrome itself (Safari had it since 2007) and somehow never actually standardized. Mozilla added support for it (under only the -webkit- name, not -moz- or unprefixed) in 2016.
This update came about four years after Tantek's famous "zero is no longer an option" comment.
