There's a closed pull request on the void-packages repository

[Draft] xbps-src: clean up fetch hook and allow mirroring
https://github.com/void-linux/void-packages/pull/38494

Description:
As an alternative to https://github.com/void-linux/void-packages/pull/38438

Allow mirroring by having multiple distfiles for the same target file name, either by url or by ">filename".