`dir-in-usr-local`

The package installs a directory in /usr/local/.... That is not allowed.

If you want to provide an empty directory in /usr/local for convenience of the local system administrator, please follow the rules in the policy manual (section 9.1.2), i.e. create the directories in the postinst maintainer script but do not fail if the operation is unsuccessful (for example, if /usr/local is mounted read-only).