Terminal output. Gzip has CRC integrity check. XZ file doesn't have anything.

Initramfs.txt (text/plain), 996 bytes, created by David Bryant on 2020-08-25 14:32:32 UTC

localhost /boot # gzip --list --verbose *.gz
method  crc     date  time           compressed        uncompressed  ratio uncompressed_name
defla dd83e75d Aug 24 23:44             6451085            15469056  58.3% initramfs-5.4.60-gentoo-x86_64.img
localhost /boot # xz --list --verbose *.xz
initramfs-5.4.60-gentoo-x86_64.xz (1/1)
  Streams:            1
  Blocks:             1
  Compressed size:    6,293.3 KiB (6,444,380 B)
  Uncompressed size:  40.1 MiB (42,024,448 B)
  Ratio:              0.153
  Check:              None
  Stream padding:     0 B
  Streams:
    Stream    Blocks      CompOffset    UncompOffset        CompSize      UncompSize  Ratio  Check      Padding
         1         1               0               0       6,444,380      42,024,448  0.153  None             0
  Blocks:
    Stream     Block      CompOffset    UncompOffset       TotalSize      UncompSize  Ratio  Check
         1         1              12               0       6,444,340      42,024,448  0.153  None