docs/data/reusables/package_registry/package-immutability.md

Public packages: To prevent confusion and build problems, {% data variables.product.prodname_dotcom %} permanently reserves a package's name and version number. Even if an entire package is deleted, you cannot reuse the deleted package name in any repository owned by the same account.

Private packages: If all versions of a private package are deleted, you can publish a package with a previously used name and version.

To revise or replace a package version, we recommend you publish a new version of your package.