There is only one file type that uses the .LDIF extension:
LDAP Data Interchange Format File
Text-based data interchange file used by LDAP directories; describes a directory, the entries contained in the directory, and changes made to the entries.
LDIF files consist of one or more entries separated by a blank line. Each entry has an optional entry ID, a required unique name, one or more object classes, and may have multiple attribute definitions.
Updated: January 9, 2016