Recommended Reading⌗

Let’s make this short and sweet. Unpacking the pbzx chunks with gives us this…

(base) iMac-Pro:payloadv2 kitty$ find *.??? -exec bash -c "echo "" \
  && echo 'Extracting {}' \
  && ./iOS-Utilities/pbzx {} >> {}.yaa" \; \
  && mkdir yaa \
  && mv *.yaa yaa/

Extracting payload.000
Flags: 0x800000
Chunk #1 (flags: 800000, length: 483560 bytes)
OK!  (8388608 bytes)
Chunk #2 (flags: 800000, length: 496884 bytes)
OK!  (8388608 bytes)
Chunk #3 (flags: 121d3c, length: 74796 bytes)
OK!  (1186816 bytes)

Extracting payload.001
Flags: 0x800000
Chunk #1 (flags: 800000, length: 462116 bytes)
OK!  (8388608 bytes)
Chunk #2 (flags: 728583, length: 413356 bytes)
OK!  (7504896 bytes)

Extracting payload.002
Flags: 0x800000
Chunk #1 (flags: 800000, length: 2164640 bytes)
OK!  (8388608 bytes)
Chunk #2 (flags: 800000, length: 2104752 bytes)
[omitted]

Extracting payload.004
Flags: 0x800000
Chunk #1 (flags: 800000, length: 8356484 bytes)
OK!  (8388608 bytes)
Chunk #2 (flags: 800000, length: 8387500 bytes)
OK!  (8388608 bytes)
Chunk #3 (flags: 800000, length: 8388608 bytes)
Warning: Can't find XZ header. Instead have 0x64c00d4c(?).. This is likely not XZ data.
Chunk #4 (flags: 800000, length: 8388608 bytes)
Warning: Can't find XZ header. Instead have 0x68576f4e(?).. This is likely not XZ data.
Chunk #5 (flags: 800000, length: 8388608 bytes)
Warning: Can't find XZ header. Instead have 0x1ae0e865(?).. This is likely not XZ data.
Chunk #6 (flags: 800000, length: 8388608 bytes)

[omitted]

Aside from a few This is likely not XZ data warnings, we’re mostly good…

Thanks to Igor Skochinsky’s answer on the Reverse Engineering StackExchange we can use yaa to extract our archives

(base) iMac-Pro:yaa kitty$ find *.???.yaa -exec bash -c "echo 'Extracting {}' \
  && yaa extract -i {} -d macOS" \;

Extracting payload.000.yaa
Error 0x821dcc00
96503 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

Extracting payload.001.yaa
Error 0x821dcc00
83193 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

Extracting payload.002.yaa
Error 0x821c4400
aborting current receiving thread
aborting entry
Truncated stream
Destroying state with non-empty in-flight queue

Extracting payload.003.yaa
Error 0x821c4400
aborting current receiving thread
aborting entry
Truncated stream
Destroying state with non-empty in-flight queue

Extracting payload.004.yaa
Error 0x821dcc00
1 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

Extracting payload.005.yaa
Error 0x821dcc00
1 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

Extracting payload.006.yaa
Error 0x821dcc00
1 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

Extracting payload.007.yaa
Error 0x821dcc00
1 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

[omitted]

Extracting payload.043.yaa
Error 0x821c4400
aborting current receiving thread
aborting entry
aborting entry
aborting entry
aborting entry
aborting entry
aborting entry
aborting entry
Destroying state with non-empty in-flight queue
63993 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

Extracting payload.044.yaa
Error 0x821c4400
aborting current receiving thread
aborting entry
Destroying state with non-empty in-flight queue
63999 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

Extracting payload.045.yaa
Error 0x821c4400
aborting current receiving thread
aborting entry
aborting entry
aborting entry
aborting entry
aborting entry
aborting entry
Destroying state with non-empty in-flight queue
63993 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

Extracting payload.046.yaa
Error 0x821dcc00
29143 entries failed to extract
ParallelArchiveExtract failed with error code 0xffffffff
extract failed

Going through the resulting macOS directory, we get an extracted copy of the root directory! Let’s see some Applications!

Screenshot of Applications directory in Finder

Yay? I mean, we’re here now but does this help us make an app bundle? Probably not. I mean, the extraction still failed and we’re missing tons of files but let’s see how things unravel as Big Sur eventually reaches Public Beta.

Until then…. ẇ̶̡̛͖͇͈͉͑̿͒̃̃̆̄̋̐͛̚͜ḛ̵͂̽͊̀̂͊̂͗͌ ̵̛̳̘͕͎͇̖͉̗̲̻̏̆̑̆̓̈̓͂̕ͅw̸͍̖͐̉͗̈́̄́͝ͅã̸̞͙̌̇͋̒͘͝i̷̢̡̡̡̛͉̮͇͓͉͇͆͐̓́̒̎͂̾̆͠t̷̥̪̠̥̆́͗͑̂͊͐̐͒̏͂̾̀͌̈́̚