moz_meta is used for storing additional bookmarks and history related information, in simple key/value pairs. moz_bookmarks_deleted is to help with synchronising with Firefox Sync. You haven't said why you want to know this information - so a general disclaimer: please don't directly modify places.sqlite in other people's profiles. We may change things at any time, and do so could cause corruption (and we have seen corruption as a result). We have APIs available for add-ons to use, if there's something missing, please file a request and discuss it in more detail.