Original sentence: It differs from the better-known Ethnologue in several ways:  It attempts to only accept languages which the editors have been able to confirm both exist and are distinct (varieties which have not been confirmed, but are inherited from another source, are tagged as "spurious" or "unattested"); it attempts to only classify languages into families which have been demonstrated to be valid; extensive bibliographic information is provided, especially for lesser-known languages, where Glottolog attempts to be comprehensive; and, to a limited extent, alternative names are listed according to the sources which use them
Edited sentence: It differs from the better-known Ethnologue in several positive ways:  It attempts to only accept languages which the editors have been able to confirm both exist and are distinct (varieties which have not been confirmed, but are inherited from another source, are tagged as "spurious" or "unattested"); it attempts to only classify languages into families which have been demonstrated to be valid; extensive bibliographic information is provided, especially for lesser-known languages, where Glottolog attempts to be comprehensive; and, to a limited extent, alternative names are listed according to the sources which use them