This block displays the links to the resources provided by the Openbook resource folder activity https://moodle.org/plugins/mod_openbook.
It is addable only to quiz activities. That block is meant to be shows during the student's quiz attempts and has to be added accordingly:

• During the setup of a quiz, a lecturer has to allow "Show blocks during quiz attempts": "Yes".
• Then she or he can add a Openbook resource folder files block, choosing what Openbook resource folder should be referenced. Only files thereof are shown (if you need files from multiple Openbook resource folders, multiple Openbook resource folder files block have to be added).
• The block should have "Where this block appears": "Display on page types" setting  set to "Any quiz module pages" or at least "Attempt quiz page".

The Openbook resource folder files block features links to the single files but also to the overall Openbook resource folder. Students are free to choose which way they prefer to go, whereby passing through Openbook resource folder obviously takes more clicks.