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

base-files: vkpurge: fix parameter expansion in list_kernels()
https://github.com/void-linux/void-packages/pull/24298

Description:
This fixes next-kernels from having too much string of their versions
stripped.

Next-kernel versions have the format "vmlinu[xz]-<ver>-next-<date>".
Thus, the string was wrongly shortened to "<date>", instead of the
correct "<ver>-next-<date>".