# tail -30 /boot/grub/grub.cfg
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/39_memtest ###
menuentry "Memtest86+-3.5" {
	insmod part_msdos
	insmod ext2
	set root='(/dev/sda,msdos2)'
	search --no-floppy --fs-uuid --set=root ac12087e-a82d-413e-8abc-7a9fc1f62ea5
	linux16 /boot/memtest-3.5.bin
}
menuentry "Memtest86+-4.20" {
	insmod part_msdos
	insmod ext2
	set root='(/dev/sda,msdos2)'
	search --no-floppy --fs-uuid --set=root ac12087e-a82d-413e-8abc-7a9fc1f62ea5
	linux16 /boot/memtest-4.20.bin
}
### END /etc/grub.d/39_memtest ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###
# rpm -qf /etc/grub.d/39_memtest 
grub2-1.99-alt7
# 

This doesn't work in my case, because in my case /boot/ is on a separate partition, and hence the path to memtest is wrong:

# mount | fgrep /boot
/dev/sda2 on /boot type ext4 (rw,nosuid,nodev,noexec,relatime,user_xattr,acl,barrier=1,data=ordered)
# 

Some more info:

# rpm -qa 'memtest*'
memtester-4.2.1-alt1
memtest86+-4.20-alt1
memtest86-3.5-alt2
#