R""(
Note: this command's interface is based heavily around installables, which you may want to read about first (nix --help).
Description
This command reads from standard input a JSON representation of a store derivation to which an installable evaluates.
Store derivations are used internally by Nix. They are store paths with
extension .drv that represent the build-time dependency graph to which
a Nix expression evaluates.
The JSON format is documented under the derivation show command.
)""