It's Just called the Custom Firmware Package, We have setup a WiKi page that details all it features, Main page
LINK HERE, It covers details for standard Humax firmware and the Customised Firmware which can be downloaded Via
THIS LINK
EDIT
I have just realised that you may have been referring to where the actual Undelete package is. Having installed the Custom Firmware package you can log into the Humax using a P.C. and you will see a
Main Web Interface page and under there a Packages page like
THIS ONE, You will be able to select Undelete from this list