Where is grubx64.efi

[Bhasker C V <bhasker@unixindia.com>]

Hi

 I have been trying to find out where does the grubx64.efi come from ?
I have a system which is EFI boot. I can see that after grub-install
/boot/efi/x86_64-efi/core.efi is created and this is copied as
efi/EFI/debian/grubx64.efi

What I am failing to understand is where does this core.efi come from ? I
went through all the packages in the netinstall cd but could not find
a single package providing this file

also dpkg -S does not return positive results about the owner of this package.

Please could someone tell me how this file gets into my system

Thanks
Bhasker C V