Displays the the combined story points of Jira issues that you have selected
Just create, or drag a new bookmark with the following code as the URL.
javascript: alert("Selected story points: " + jQuery(".ghx-selected [title='Story Points']").map((i, s) => Number(s.innerText)).toArray().reduce((a,s) => a+s));
Go to your Jira's backlog or active sprint, and select one or more tickets. Press the bookmark, and you will see the following alert box:
Your Jira instance has to have jQuery, and your browser should support ES6
Tested on a newish version of Chrome and Safari, and some version of Jira. Your mileage might vary.