revision = readFirstLine(refFile);
                } else if (Files.exists(gitDir.resolve("packed-refs"))) {
                    // Check packed references for commit ID
                    Pattern p = Pattern.compile("^([a-f0-9]{40}) " + refName + "$");
                    try (Stream<String> lines = Files.lines(gitDir.resolve("packed-refs"))) {
                        revision = lines.map(p::matcher)

// UnsealETag unseals the etag using the provided object key.
// It does not try to decrypt the ETag if len(etag) == 16
// because such ETags indicate that the S3 client hasn't sent
// an ETag = MD5(object) and the backend has picked an ETag value.
func (key ObjectKey) UnsealETag(etag []byte) ([]byte, error) {
	if !IsETagSealed(etag) {
		return etag, nil
	}
	mac := hmac.New(sha256.New, key[:])
	mac.Write([]byte("SSE-etag"))

 * configuration of a project
 * 2. The integ-test-zip and zip distributions have the exact same
 * filename, so they must be placed in different directories.
 * 3. We provide a packed and an unpacked variant of the distribution
 * - the unpacked variant is used by consumers like test cluster definitions
 * 4. Having per-distribution sub-projects means we can build them in parallel.
 */