Blending modes - Something lost in translation?

[twinquartz]

I just received issue #10 of the only photo magazine
I subscribe to: c't Digital Photography. Among other things, it
contains a 22-page in-depth article about Blending mode techniques
in Photoshop, which taught me several new tricks.

The article on Dedicated Selection Tools, however, is puzzling.
Here is the opening sentence:
The best way to start any complex selection using Photoshop is to
apply a double blend to the green channel using the Multiply and Overlay blending modes.

I am completely lost . If anyone has the original German text, what does it say?