Function merge_pack 

pub fn merge_pack(pack: &ContentPack, settings: &mut Settings) -> MergeSummary

Merge a validated pack into settings, returning only the summary counts. Thin wrapper over merge_pack_tracked for the content-pack import path, which has no uninstall and so doesn’t need the AddedContent record.

Strips any per-step asset first: a portable pack is unsigned and carries no image bytes, so an asset value could only be an arbitrary local path a malicious pack smuggled in — only the signed-plugin installer is allowed to populate asset, and it does so with a backend-controlled sidecar path. Mirror of the stripping export_pack does on the way out.