Referring to an origin input in a package variant

[Jake]

Hello

>From [1], the old input style (which is now deprecated) allows us to assign
a string label to an origin.  E.g. if we have an origin called my-input

(define my-input (origin ...))

then the old input style allows us to provide it as an input to a package
and give it a label at the same time, like so:

(define pkg-a
    (package (inputs `(("my-input-label" ,my-input)))))

This label can be useful when defining a package variant.  E.g.

(inputs (modify-inputs (package-inputs pkg-a)
              (delete "my-input-label")))

With the new input style, we write:

(package (inputs (list my-input)))

Does our input still have a label we can refer to in a package variant?  If
the input was a package, we could refer to it by the package's name
string.  But what about for an origin input?

Thanks
Jake

[1] https://guix.gnu.org/manual/en/html_node/package-Reference.html