breaks doesn't seem to actually work with new version ranges.

[sisby-folk]

https://mclo.gs/OcF90a9

Here, the mod rpgstats declares a breaks for switchy for versions >=2.0.0 <2.0.3, which quilt loader seems to correctly parse as [>2.0.0 <2.0.3]

but in practicality, the version 2.7.3 breaks. This seems to imply that the broken version can be >2.0.0 OR <2.0.3 rather than actually being within that range. Either that or the version is totally unused, which seems unlikely - what's going on here? is it a bad version string?

[LostLuma]

is it a bad version string?

That is indeed the case, see the specification:

String
Should be a single version specifier defining the versions this dependency applies to.

If you want to match multiple versions you need to use one of the other two formats (preferring the new object one).