Yes. The Go implementation from Google is under the BSD licence.
There's also the GNU implementation in GCC that's under the GNU GPL 3 licence. Moreover, the specification itself doesn't seem to have any licencing requirements at all.
So you're absolutely right: Go is the very opposite of proprietary.
Golang is trademarked by Google. It’s a corporate faux open source project. FAANG is co-opting free labor. Even open source platforms like GitHub are a wolf in sheep’s clothing. What Microsoft or Google can’t defeat they acquire.
FOSSmarks (hosted by FSF, and writers include people affiliated with FSF)[0]:
>Trademarks and FOSS are not incompatible; instead, trademarks are legal tools strongly aligned with FOSS principles. A trademark is an assurance that the recipient of the goods or services is receiving a product of known source and qualities. Controlling how a FOSS project trademark is used protects the community and its software, by preventing use of the trademark in ways that are harmful to the reputation of the community or the software.
Linux is a registered trademark of Linus Torvalds[1]. GNU is a registered trademark of the FSF[2]. Your definition of "proprietary" isn't shared by virtually anyone, and would make virtually everything "faux open source", including the "open source os" project you originally worried about Go being integrated into.
