Metadata is EagleFiler-specific information such a record’s title, from name, checksum, source URL, tags, and notes. It is stored inside the .eflibrary file.
EagleFiler will automatically backup a library’s metadata when it’s opened and also periodically thereafter. You can manually backup the metadata by holding down the Option key and choosing Backup Metadata from the File menu.
Metadata is backed up to invisible EagleFiler Metadata.plist files inside the library folder. These are standard Mac OS X property lists that can be viewed in TextEdit and processed by many other programs.
Normally when you import a file it will have no metadata except that which can be extracted from the file itself, e.g. the title and author of a PDF or the source URL of a Web archive. If you import a file that has backed-up metadata, EagleFiler will restore all of the metadata from the backup. For example, if a .eflibrary file were damaged, you could create a new library, import the Files folder from the old library, and all the metadata would be preserved.