Domino, Public Folder Archives, Mailbox Archives, File System Archives etc all use the same logical structure, and permissions browser can be used against any Enterprise Vault archive and does not have any interactions or bearing on the source.
i.e if your exchange is offline and you are viewing mailboxes in permissions browser, we do not require exchange to be running to view it, all we need is access to sql as we are just reading form specific tables to see what users and groups have permissions to which folders