Found a solution. I pasted this bit of code at the end of “global.js” to allow external links to open in a new tab. It’s not quite what I wanted (to have set a single link to open in a new tab) but it should perform the same functionality. Here is the code:
const links = document.links;
for (let i = 0, linksLength = links.length ; i < linksLength ; i++) {
if (links[i].hostname !== window.location.hostname) {
links[i].target = '_blank';
links[i].rel = 'noreferrer noopener';
}
}