modified = time.Unix(epoch.Unix()+secs, nsecs)
			}
		case unixExtraID, infoZipUnixExtraID:
			if len(fieldBuf) < 8 {
				continue parseExtras
			}
			fieldBuf.uint32()              // AcTime (ignored)
			ts := int64(fieldBuf.uint32()) // ModTime since Unix epoch
			modified = time.Unix(ts, 0)
		case extTimeExtraID:
			if len(fieldBuf) < 5 || fieldBuf.uint8()&1 == 0 {
				continue parseExtras
			}

			// This is wrong and leads to an output file that mangles the
			// atime and ctime fields, which are often left unused.
			//
			// In order to continue reading tar files created by former, buggy
			// versions of Go, we skeptically parse the atime and ctime fields.
			// If we are unable to parse them and the prefix field looks like