There is an updated pull request by Duncaen against master on the void-packages repository

https://github.com/Duncaen/void-packages icu-70.1
https://github.com/void-linux/void-packages/pull/35006

icu-70.1, firefox-96.0
[ci skip]

Maybe I could add harfbuzz>=3.0.0, that would pull in the electron packages though, but there are many overlapping ones.

A patch file from https://github.com/void-linux/void-packages/pull/35006.patch is attached