Bautismo Libro Reservado

while researching my Garcia lineage, I can across
this statement: los nombres de los Padres, Abuelos Paternos y Maternos se hallan
en el Libro Reservado. I happen to have the information, Regarding the daughter, Maria Anacleta Teresa Garcia Macias, born July 3, 1861, familysearch , bautismos 1861-1862, IMAGE#158, Aguascalientes, Asuncion de Maria, Parents were, Nicolas
Garcia Reyes and Pantaleona Macias, Macias; paternal grandparents were, Jose Camilo
Garcia Bocanegra and Brigida Reyes Losando; maternal; Jose Macias and YsavelMacias
(batch#) C60483-2 and GS Film number: 299485. what is the meaning of Libro Reservado? Gracias, Arturo de Leon