src/vs/workbench/services/path/common/pathService.ts/AbstractPathService/findDefaultUriScheme
class AbstractPathService:	static findDefaultUriScheme(environmentService: IWorkbenchEnvironmentService, contextService: IWorkspaceContextService): string {
		if (environmentService.remoteAuthority) {
			return Schemas.vscodeRemote;
		}

		const virtualWorkspace = getVirtualWorkspaceScheme(contextService.getWorkspace());
		if (virtualWorkspace) {
			return virtualWorkspace;
		}

		const firstFolder = contextService.getWorkspace().folders[0];
		if (firstFolder) {
			return firstFolder.uri.scheme;
		}

		const configuration = contextService.getWorkspace().configuration;
		if (configuration) {
			return configuration.scheme;
		}

		return Schemas.file;
	}