partition.gdisk.gpt.raw contains the partition table backed up by gdisk, and backup.dd.img.raw contains sectors 0 to 688168 (the first 352342016 bytes, right before the Android data begins). Both have been compressed by xz (xz -d [filname] to decompress).
/tmp > gdisk -l backup.dd.img.raw
GPT fdisk (gdisk) version 1.0.0
Warning! Disk size is smaller than the main header indicates! Loading
secondary header from the last sector of the disk! You should use 'v' to
verify disk integrity, and perhaps options on the experts' menu to repair
the disk.
Caution: invalid backup GPT header, but valid main header; regenerating
backup header from main header.
Warning! Error 25 reading partition table for CRC check!
Warning! One or more CRCs don't match. You should repair the disk!
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: damaged
****************************************************************************
Caution: Found protective or hybrid MBR and corrupt GPT. Using GPT, but disk
verification and recovery are STRONGLY recommended.
****************************************************************************
Disk backup.dd.img.raw: 688168 sectors, 336.0 MiB
Logical sector size: 512 bytes
Disk identifier (GUID): 6C014B70-F9AF-6B2D-894A-AD19C996D71F
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 60620766
Partitions will be aligned on 8-sector boundaries
Total free space is 4029 sectors (2.0 MiB)
Number Start (sector) End (sector) Size Code Name
1 40 131111 64.0 MiB EF00 ESP
2 131112 262183 64.0 MiB 0700 reserved
3 262184 294951 16.0 MiB 0700 boot
4 294952 327719 16.0 MiB 0700 recovery
5 327720 360487 16.0 MiB 0700 fastboot
6 360488 393255 16.0 MiB 0700 reserved_1
7 393256 524327 64.0 MiB 0700 test
8 524328 589863 32.0 MiB 0700 panic
9 589864 622631 16.0 MiB 0700 factory
10 622632 655399 16.0 MiB 0700 misc
11 655400 688167 16.0 MiB 0700 config
12 688168 2785319 1024.0 MiB 0700 cache
13 2785320 3309607 256.0 MiB 0700 logs
14 3309608 6455335 1.5 GiB 0700 system
15 6455336 21135399 7.0 GiB 0700 data
16 21137408 21399551 128.0 MiB 0C01 Microsoft reserved ...
17 21399552 45137919 11.3 GiB 0700 Basic data partition
18 49233920 60618751 5.4 GiB 2700 Basic data partition
19 45137920 49233919 2.0 GiB 8300