Although I applaud the efforts, at the current state that's just sugarcoating the nastiness of code-executing installers. A package installation should basically just deploy the components of a passive package archive to the filesystem and leave any actions to the package manager. This solution doesn't even provide a generic interface e.g. to run a query which file would be provided by which package or to which package a specific file in the filesystem belongs to. The installation process still relies on mostly uncontrollable code execution.