From: Justin M. Forbes on
gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1801#note_9697...
This seems correct, looking at a dist-dump-variables.
```
BASEVERSION=5.19.0-0.rc0.d1dc87763f40.10 (perhaps misleadingly named?)
SPECVERSION=5.19.0
UPSTREAM_TARBALL_NAME=5.18-11972-gd1dc87763f40
```
If we needed to for some RHELish reason, I would be okay with using
UPSTREAM_TARBALL_NAME, but SPECVERSION is optimal for Fedora. I can see how
it would be easy to confuse the 2, without looking at the code, I would expect
BASEVERSION and SPECVERSION to have their values flipped.