Newbie user question: What do the columns shown by "guix package -I" mean?

[Rodrigo Morales]

Inexperienced GUIX user here. I have a question. What's the formal names
for the information presented in the columns shown by `guix package -I'?
(see example of output below)

As I'm learning how to use Guix, I'm taking notes so I want to make sure
that I'm using the correct names in my notes. By intuition, I can say
that the first column is the package name, the second column is the
package version. What about the 3rd and the 4th column?

,----
| guix package -I
`----

,----
| rsync                   3.2.7           out
/gnu/store/72isv0hc8wp65bajhdh8jqvd3m9w0p4x-rsync-3.2.7
| tmux                    3.3a            out
/gnu/store/ynvhs65sh4nq5rd6b1pnlh2h7d94jk1c-tmux-3.3a
`----