Reliable rate limit tracking without contract

I understand that OpenVSX has introduced rate limiting to make it more sustainable.

I'm supportive of this, but right now there doesn't seem to be any way to actually figure out our traffic. The only thing we have received is a heavyhanded demand from a salesperson to agree to an aggressive contract.

It would be great for consumers to be able to provide a header with a secret token that we can use to reliably measure our actual traffic.