initramfs images can contain multiple segments, and it’s common nowadays to have a short
cpio archive containing early-boot files (such as microcode updates) before the main, compressed,
cpio archive. In such circumstances you can use a tool such as
lsinitramfs (on Debian and derivatives) or
lsinitrd (on Fedora, RHEL and derivatives) to view the full contents of the initramfs.
lsinitramfs doesn’t support multi-segment files in general, but it does handle the special case described above.
lsinitrd also supports the special case described above, I’m not sure whether it supports other multi-segment images.)