For onprem those files can be imported using the import-spweb powershell command however this does not have a 1-1 counterpart in the SharePoint online powershell module.
I suspect MSFT support may have a way, but it appears they do not document it.
For onprem those files can be imported using the import-spweb powershell command however this does not have a 1-1 counterpart in the SharePoint online powershell module.
I suspect MSFT support may have a way, but it appears they do not document it.