Nothing clever here at all: just takes a random sample of the bookmarks in a given folder, with a barebones UI.
Based off the Chrome API tutorial code, hence the inclusion of the license they use.
You can use it directly from the source code by going to the Chrome extensions page, entering developer mode, and adding these files' folder as an extension. I will consider adding this to the Chrome Web Store if there is any wider interest in actually taking random samples of bookmark folders.