For unlimited file storage in chrome app that is known as bundled app, we must use FileEntry through chrome.fileSystem.chooseEntry. so that data is written to computer’s file system which is accessible by user.
We can use file API without calling chrome.filesystem.chooseEntry.
The unlimitedStorage object allows unlimited storage. If we are writing to external filesystem, after calling chrome.filesystem.chooseEntry, there are no limits and don’t need unlimitedstorage permission.