The first code snippet is from: /plugins/org.apache.cordova.file/www/File.js

File.js

/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
*/

/**
 * Constructor.
 * name {DOMString} name of the file, without path information
 * fullPath {DOMString} the full path of the file, including the name
 * type {DOMString} mime type
 * lastModifiedDate {Date} last modified date
 * size {Number} size of the file in bytes
 */

var File = function(name, localURL, type, lastModifiedDate, size){
    this.name = name || '';
    this.localURL = localURL || null;
    this.type = type || null;
    this.lastModified = lastModifiedDate || null;
    // For backwards compatibility, store the timestamp in lastModifiedDate as well
    this.lastModifiedDate = lastModifiedDate || null;
    this.size = size || 0;

    // These store the absolute start and end for slicing the file.
    this.start = 0;
    this.end = this.size;
};

/**
 * Returns a "slice" of the file. Since Cordova Files don't contain the actual
 * content, this really returns a File with adjusted start and end.
 * Slices of slices are supported.
 * start {Number} The index at which to start the slice (inclusive).
 * end {Number} The index at which to end the slice (exclusive).
 */
File.prototype.slice = function(start, end) {
    var size = this.end - this.start;
    var newStart = 0;
    var newEnd = size;
    if (arguments.length) {
        if (start < 0) {
            newStart = Math.max(size + start, 0);
        } else {
            newStart = Math.min(size, start);
        }
    }

    if (arguments.length >= 2) {
        if (end < 0) {
            newEnd = Math.max(size + end, 0);
        } else {
            newEnd = Math.min(end, size);
        }
    }

    var newFile = new File(this.name, this.localURL, this.type, this.lastModified, this.size);
    newFile.start = this.start + newStart;
    newFile.end = this.start + newEnd;
    return newFile;
};


module.exports = File;

Please check, here for a screen shot of my inspector
http://i.imgur.com/8GoEboO.png