Anki is open source "flash card" software. The decks in this repository are made to prepare for the exam by questioning you on the material.
Most .txt files will be decks. Only ...-info.txt contain metadata.
Install Anki if you have not already. It is available in the repositories, but that seems to be broken. Download from https://apps.ankiweb.net/#download.
With Ctrl+I (or File -> Import) you can import decks. Use "Allow HTML" when importing these decks.
To add changes, request write permissions so you can push to the repository.
Export the deck using File -> Export. The format "Cards in Plain Text" is preferred, but you can use a binary package as well if you have pictures or something.
Use an -info.txt file to comment on a card deck, e.g. give status such as
"todo: architecture slides 44-64".
If your contributions fit in an existing deck, just add them to that deck. Feel free to remove cards (if you're quite sure they're silly), improve cards, merge/split cards, etc.