How to download all videos of a playlist (full playlist) from YouTube

I was looking for an simple way how to download all videos of a YouTube playlist in a batch.

How i fixed it:
I used firefox and these two Add-ons:
- BYTubeD - Bulk YouTube Video Download
- DownloadThemAll

How to download all videos of the playlist:
- Do a search on YouTube for the Playlist you want to grab (set the search filter to "Playlist") and select "Show all videos".
- Use the BYTubeD Add-on to generate a local HTML page with links to the desired videos which then opens in firefox
- On this newly opened page use DownloadThemAll to download all files

I found the solution in the (german) video: