[erik_seaberg]

The branding has been churned like crazy. As far as I can tell, the first .NET version that officially supported (almost?) the complete API on Linux was released last month, so we’d have to sign up for being an early adopter.

[phillipcarter]

"the complete API" is a bit of a misnomer, since there have been new APIs and runtime capabilities that aren't available to the Windows-only, older runtime (The .NET Framework). This has been the case since at least .NET Core 2.1 but has continued ever since.

There are several APIs in the older runtime that are intentionally not brought forward, and what I believe you're referring to is this announcement: https://github.com/dotnet/announcements/issues/130

The remaining APIs are (mostly) AppDomains, Remoting, Web Forms, WCF server, and Windows Workflow, most of which is either an acknowledged "this was the wrong way to do it so we won't bring it forward" (e.g., Remoting) or tied to Windows anyways (e.g., WCF).