 *         id: {string},
       *         // `on-event="handler"` metadata
       *         events: [
       *           {
       *             name: {string},   // event name
       *             value: {string},  // handler method name
       *           }, ...
       *         ],
       *         // Notes when the template contained a `<slot>` for shady DOM
       *         // optimization purposes
       *         hasInsertionPoint: {boolean},
       *         // For nested `<template>`` nodes, nested t