Consider the package expr evaluates to.

[znavko]

I cannot understand this string from manual:
"Consider the package expr evaluates to."

I cannot translate it using dictionary. Please, could you rephrase it for me?

There the link to `guix build --expression` make some sense: "-e expr 

        Build the package or derivation expr evaluates to. "

As I understand: To build the package or derivation that responds to expression 
(or that contains expression). Am I right?

But that first line I definitely can't understand.