[Nemo157]

The standard separator for build metadata fields is a period, since the section is ignored for version comparison it doesn’t really matter, but the spec does specify it (and some tools may display separate fields differently).

[eridius]

Oh you're right. I glanced at the spec and saw that it defined build metadata as [0-9A-Za-z-] but didn't realize that it was actually defining this as a dot-separated series of components where each component was [0-9A-Za-z-].