phpBB extension

Since phpBB 3.1.x forums now support proper extensions, is it possible to offer the tooltip functionalities that are provided by the old workarounds? I'd like to do the work myself if I could, but I'm pretty overwhelmed by how complex the phpBB framework seems to be.

I'm referring specifically to this functionality which no longer works for current versions of phpBB because the javascript files in the guide don't seem to look like they used to or in some case don't exist at all anymore...

If it's too much work I totally understand, but maybe it's just a couple of tweaks to the existing solution, in which case I'd be very grateful if a "proper" extension could be provided.