Recall from the previous section what you will first see when the sudo make install command executes (reproduced as follows for your convenience):
$ sudo make install
sh ./arch/x86/boot/install.sh 5.4.0-llkd01 arch/x86/boot/bzImage \
System.map "/boot"
Clearly, it's (install.sh) a script being executed. Internally, as part of its work, it copies the following files into the /boot folder, with the name format typically being <filename>-$(uname -r):
System.map-5.4.0-llkd01, initrd.img-5.4.0-llkd01, vmlinuz-5.4.0-llkd01, config-5.4.0-llkd01
The initramfs image is built as well. A shell script named update-initramfs performs this task (which is itself a convenience wrapper over another script called mkinitramfs(8) that performs the actual work). Once built, the initramfs image is also copied into the /boot directory, seen as initrd.img-5.4.0-llkd01 in the preceding output snippet.
If at all a file being copied...