Author of the post here, happy to chat in the comments!
The TLDR is that it's a tweak to SemVer style versioning, where instead of trying to cut things up into bug fixes, enhanecements and breaking changes you use the segments to communicate how much effort is required to adopt the new version.
This version scheme has been growing in popularity in the Python community recently, partly because it's effectively what many projects already do today. So thought I'd share it more widely again.
This has been discussed on HN before:
- https://news.ycombinator.com/item?id=39039414
- https://news.ycombinator.com/item?id=39400576
