roxygen2 7.0.0 (2019-11-12) had the breaking change

• Using @docType package no longer automatically adds a -package alias.
  Instead document _PACKAGE to get all the defaults for package documentation

from 29db38f.

However, thousands of packages still use the old way (that was still recommended a year ago)

#' @docType package
#' @name pkgname
NULL

not being aware that they should

• either document the new "special sentinel" _PACKAGE
• or manually add @aliases <pkgname>-package

because they no longer automatically get that alias that is required for a package overview page to be found via package?pkgname. As a consequence, CRAN now has thousands of packages where this help request no longer works.

Could roxygen2 warn users when there is a @docType package block without corresponding @aliases (and possibly recommend the new _PACKAGE feature)?