I'm not sure I fully understand the provenance of the code here, but I could just be being a bit thick. The files in the change request show the copyright as "2

I'm not sure I fully understand the provenance of the code here, but I could just be being a bit thick. The files in the change request show the copyright as "2018 The Go Authors", but some of the commentary hints that this is code donated from the Sourcegraph implementation. If this is the case, does that mean Sourcegraph has transferred the copyright to the Go authors?