The following files are officially served by Udacity and should be accessible even if YouTube is blocked or if you want an offline access.
Video files are numbered and zipped per unit and contain a playlist file for convenience. You can use for example VLC player to play them.
If you have a terminal or any download manager, here is a text file with all the links to recursively download all files at once. Use
wget -r urllist.txt or
wget -i urllist.txt to download the files.
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