Search notes:

make mrproper

make mrproper removes all generated files, config and various backup files:

include/config include/generated
arch/$(SRCARCH)/include/generated
.objdiff
debian
snap
tar-install
.config,
.config.old
.version
Module.symvers
certs/signing_key.pem
certs/x509.genkey
vmlinux-gdb.py
rpmbuild
rust/libmacros.so

See also

make distclean

make cleandocs and make kselftest-clean