The need to find SharePoint documents with sensitivity labels might arise during a tenant divestiture to decrypt the documents before the split. As it turns out, searches against the SharePoint InformationProtectionLabelId property is a good way to find the files. After that, the need arises to decrypt the documents, which is where Microsoft Purview eDiscovery (premium) might come in handy.
https://office365itpros.com/2023/06/29/find-sharepoint-documents-labels/
