extensions/git/src/commands.ts/CommandCenter/syncAll
class CommandCenter:	async syncAll(): Promise<void> {
		await Promise.all(this.model.repositories.map(async repository => {
			const config = workspace.getConfiguration('git', Uri.file(repository.root));
			const rebase = config.get<boolean>('rebaseWhenSync', false) === true;

			const HEAD = repository.HEAD;

			if (!HEAD || !HEAD.upstream) {
				return;
			}

			await repository.sync(HEAD, rebase);
		}));
	}