1. A method comprising: using a computing system including one or more machines, to perform one or more of the following acts, accessing a main file name of a main file; accessing a relationship definition file having at least one relationship definition associated with a package of data items, the at least one relationship definition identifying at least one class of relationships between data items included in the package of data items, the at least one relationship definition associating the main file with information stored in a related file, the at least one relationship definition including a template string; and accessing the related file by adding a portion of the template string to a portion of the main file name to generate a related file name, wherein the information stored in the related file is related to information contained in the main file, and wherein the information stored in the related file is for use in rendering the main file, by an electronic document rendering application, without altering the information contained in the main file.
1. A method comprising: using a computing system including one or more machines, to perform one or more of the following acts, accessing a main file name of a main file; accessing a relationship definition file having at least one relationship definition associated with a package of data items, the at least one relationship definition identifying at least one class of relationships between data items included in the package of data items, the at least one relationship definition associating the main file with information stored in a related file, the at least one relationship definition including a template string; and accessing the related file by adding a portion of the template string to a portion of the main file name to generate a related file name, wherein the information stored in the related file is related to information contained in the main file, and wherein the information stored in the related file is for use in rendering the main file, by an electronic document rendering application, without altering the information contained in the main file. 6. The method of claim 1 , wherein the at least one relationship definition includes a first pattern string, and accessing the related file comprises: substituting a substring of the main file name for a first wildcard symbol in a first pattern string; and substituting the first pattern string, including the substituted substring of the main file name, for a wildcard-identifying symbol of the template string t to generate the related file name.