src/vs/workbench/contrib/webview/browser/baseWebviewElement.ts/BaseWebview/localLocalhost
class BaseWebview:	private async localLocalhost(id: string, origin: string) {
		const authority = this._environmentService.remoteAuthority;
		const resolveAuthority = authority ? await this._remoteAuthorityResolverService.resolveAuthority(authority) : undefined;
		const redirect = resolveAuthority ? await this._portMappingManager.getRedirect(resolveAuthority.authority, origin) : undefined;
		return this._send('did-load-localhost', {
			id,
			origin,
			location: redirect
		});
	}