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

https://github.com/Johnnynator/void-packages xdg
https://github.com/void-linux/void-packages/pull/21746

xbps-src: allow loading xbp-src.conf from XDG compliant dirs
None

A patch file from https://github.com/void-linux/void-packages/pull/21746.patch is attached