Users see the following warnings in their log on Fabric:
[ForkJoinPool-1-worker-9/WARN]: Mod ends_delight uses the version refabricated-1.21.1-2.5 which isn't compatible with Loader's extended semantic version format (Could not parse version number component 'refabricated'!), SemVer is recommended for reliably evaluating dependencies and prioritizing newer version

Tested with https://modrinth.com/mod/ends-delight/version/refabricated-1.21.1-2.5

Valid semver would be 2.5.0+refabricated.1.21.1

https://semver.org/