“The original GitHub Copilot extension that provides inline completions remains closed source – but in the following months we plan to have that functionality be provided by the open sourced GitHub Copilot Chat extension .”
Microsoft open sourced the Copilot Chat extension, prompts and telemetry included. Inline completions, the feature people actually paid for, stays closed. The model backend and the Copilot service are not part of it. The editor is open, and the product is still the subscription.