od Infocatcher (Vývojář) v Čec. 6, 2013 · trvalý odkaz

What this custom script should do?

An example based on http://www.xuldev.org/firegestures/makescripts.php :

// Open "dragged" link in new private tab
var srcNode = FireGestures.sourceNode;
var linkURL = FireGestures.getLinkURL(srcNode);
if (!linkURL)
    throw "Not on a link";
FireGestures.checkURL(linkURL, srcNode.ownerDocument);
privateTab.readyToOpenTab(true);
gBrowser.selectedTab = gBrowser.addTab(linkURL, {
    charset: srcNode.ownerDocument.characterSet,
    relatedToCurrent: true
});


Also you can found some examples here:
https://github.com/Infocatcher/Private_Tab#api-functions