playground: about the v query parameter

[Manlio Perillo]

The recent version of the playground allows selecting the "Go release" or "Go dev branch" compiler using a drop-down list.

The playground also accepts the v query parameter, and, when set, a new "Backend: $v" entry is added to the drop-down.  What does Backend means here?

Here are some examples for the v query parameter

  1. v=go1.1   uses the Go current release (go1.17.8)

  2. v=gotip    correctly uses The Go dev branch

  3. v=amd64 causes an "Error communicating with remote server."

I suspect that v also accept tags, in fact a server error is also triggered when v=go1 and v=linux.

Thanks

Manlio