a free enhanced file manager:
android file browser, can use system relative software to open apk/image/audio/video/pdf/document files;
support new/copy/paste/delete/property operations on folder/file; sort/search folder/file;
view/decompress zip and rar file;
view gif image file;
the most important, this tool can view permissions of apk files on your internal storage and external storage.
Droid File Manager free for your Android phone