Whats here

5.10.27-v8+_modules.bz2  
The modules to go with kernel-5.10.27-v8+.  Untar to /lib on the root filesystem of the Pi. It should give you /lib/5.10.27-v8+ 

bcm2711-rpi-4-b.dtb
The Device Tree Binary from kernel-5.10.27-v8+.

cmdline.txt
My working cmdline.txt It has my root=UUID=. That will need to be updated to just work.

cmdline.txt_LVM_no_initrd
Not required. I was trying root in LVM without an initrd.

config.txt
My config.txt
Expects to load kernel-5.10.27-v8+, initramfs_rootinLVM_1, bcm2711-rpi-4-b.dtb and any overlays.
File names have to be hard coded. 

COPYING.linux
The kernel licence. Required to share this. 

LICENCE.broadcom
The broadcom licence, covering the fixup* and start* files below. Required to share this. 
fixup4cd.dat
fixup4.dat
fixup4db.dat
fixup4x.dat
start4cd.elf
start4db.elf
start4.elf
start4x.elf

initramfs_rootinLVM_1
The initramfs that does eveything to mount the root filesystem inside LVM.

initrd.bz2
The talball of /root/initrd as used to assemble initramfs_rootinLVM_1.
Untar it to /root

kernel-5.10.27-v8+
The Raspberry Pi Foundation kernel-5.10.27-v8+, built from the Raspberry Pi Foundation default config.
The device mapper configuration changes were checked and possibly amended. 

overlays
The overlays from the kernel build.


On the Pi, the Device Tree Binary and overlays must match the kernel and are built as part of the kernel.
They don't change often but it may matter when they do.