The Web Monetization extension received an update today to also include event details in the listener callback:
webmonetization.set_listener(function(self, event, details)
pprint(details)
end)
Details table:
{
paymentPointer = "$ilp.uphold.com/QkG86UgXzKq8",
assetScale = 9,
amount = "26009",
requestId = "a1f728aa-21e0-4376-ae99-0ccb22642956",
assetCode = "XRP"
}