There is a new pull request by mmnmnnmnmm against master on the void-packages repository

https://github.com/mmnmnnmnmm/void-packages firefox-esr
https://github.com/void-linux/void-packages/pull/24508

firefox-esr: update to 68.12.0
This is the final release of 68 branch, next version will be firefox-esr 78.

A patch file from https://github.com/void-linux/void-packages/pull/24508.patch is attached