> scala test.scala -Xkind-projector:help
-Xkind-projector  Allow `*` as type lambda placeholder to be compatible with
                  kind projector. When invoked as -Xkind-projector:underscores
                  will repurpose `_` to be a type parameter placeholder, this
                  will disable usage of underscore as a wildcard.
                  Default disable
                  Choices: disable, , underscores

scala> :settings -Wunused:help
-Wunused  Enable or disable specific `unused` warnings
          Choices:
          - nowarn,
          - all,
          - imports :
                Warn if an import selector is not referenced.,
          - privates :
                Warn if a private member is unused,
          - locals :
                Warn if a local definition is unused,
          - explicits :
                Warn if an explicit parameter is unused,
          - implicits :
                Warn if an implicit parameter is unused,
          - params :
                Enable -Wunused:explicits,implicits,
          - patvars :
                Warn if a variable bound in a pattern is unused,
          - linted :
                Enable -Wunused:imports,privates,locals,implicits