Make Google Sites work in TenFourFox/IWPPC again (with Firefox 78 or higher user agent):

google sites userscript.txt

// ==UserScript==
// @name        Google Sites
// @namespace   https://sites.google.com/*
// @include     https://sites.google.com/*
// @run-at      document-start
// @version     1
// @grant       none
// ==/UserScript==
!function () {
  return function e(t, r, n) {
    function i(s, a) {
      if (!r[s]) {
        if (!t[s]) {
          var c = 'function' == typeof require && require;
          if (!a && c) return c(s, !0);
          if (o) return o(s, !0);
          var u = new Error('Cannot find module \'' + s + '\'');
          throw u.code = 'MODULE_NOT_FOUND',
          u
        }
        var f = r[s] = {
          exports: {
          }
        };
        t[s][0].call(f.exports, function (e) {
          return i(t[s][1][e] || e)
        }, f, f.exports, e, t, r, n)
      }
      return r[s].exports
    }
    for (var o = 'function' == typeof require && require, s = 0; s < n.length; s++) i(n[s]);
    return i
  }
}() ({
  1: [
    function (e, t, r) {
      'use strict';
      Object.defineProperty(r, '__esModule', {
        value: !0
      });
      r.ContentRect = function (e) {
        if ('getBBox' in e) {
          var t = e.getBBox();
          return Object.freeze({
            height: t.height,
            left: 0,
            top: 0,
            width: t.width
          })
        }
        var r = window.getComputedStyle(e);
        return Object.freeze({
          height: parseFloat(r.height || '0'),
          left: parseFloat(r.paddingLeft || '0'),
          top: parseFloat(r.paddingTop || '0'),
          width: parseFloat(r.width || '0')
        })
      }
    },
    {
    }
  ],
  2: [
    function (e, t, r) {
      'use strict';
      Object.defineProperty(r, '__esModule', {
        value: !0
      });
      var n = e('./ContentRect'),
      i = function () {
        function e(e) {
          this.target = e,
          this.$$broadcastWidth = this.$$broadcastHeight = 0
        }
        return Object.defineProperty(e.prototype, 'broadcastWidth', {
          get: function () {
            return this.$$broadcastWidth
          },
          enumerable: !0,
          configurable: !0
        }),
        Object.defineProperty(e.prototype, 'broadcastHeight', {
          get: function () {
            return this.$$broadcastHeight
          },
          enumerable: !0,
          configurable: !0
        }),
        e.prototype.isActive = function () {
          var e = n.ContentRect(this.target);
          return !!e && (e.width !== this.broadcastWidth || e.height !== this.broadcastHeight)
        },
        e
      }();
      r.ResizeObservation = i
    },
    {
      './ContentRect': 1
    }
  ],
  3: [
    function (e, t, r) {
      'use strict';
      Object.defineProperty(r, '__esModule', {
        value: !0
      });
      var n = e('./ResizeObservation'),
      i = e('./ResizeObserverEntry'),
      o = [
      ],
      s = function () {
        function e(e) {
          this.$$observationTargets = [
          ],
          this.$$activeTargets = [
          ],
          this.$$skippedTargets = [
          ];
          var t = function (e) {
            if (void 0 === e) return 'Failed to construct \'ResizeObserver\': 1 argument required, but only 0 present.';
            if ('function' != typeof e) return 'Failed to construct \'ResizeObserver\': The callback provided as parameter 1 is not a function.'
          }(e);
          if (t) throw TypeError(t);
          this.$$callback = e
        }
        return e.prototype.observe = function (e) {
          var t,
          r = c('observe', e);
          if (r) throw TypeError(r);
          u(this.$$observationTargets, e) >= 0 || (this.$$observationTargets.push(new n.ResizeObservation(e)), t = this, o.indexOf(t) < 0 && (o.push(t), b()))
        },
        e.prototype.unobserve = function (e) {
          var t = c('unobserve', e);
          if (t) throw TypeError(t);
          var r = u(this.$$observationTargets, e);
          r < 0 || (this.$$observationTargets.splice(r, 1), 0 === this.$$observationTargets.length && a(this))
        },
        e.prototype.disconnect = function () {
          this.$$observationTargets = [
          ],
          this.$$activeTargets = [
          ],
          a(this)
        },
        e
      }();
      function a(e) {
        var t = o.indexOf(e);
        t >= 0 && (o.splice(t, 1), $())
      }
      function c(e, t) {
        return void 0 === t ? 'Failed to execute \'' + e + '\' on \'ResizeObserver\': 1 argument required, but only 0 present.' : t && t.nodeType === window.Node.ELEMENT_NODE ? void 0 : 'Failed to execute \'' + e + '\' on \'ResizeObserver\': parameter 1 is not of type \'Element\'.'
      }
      function u(e, t) {
        for (var r = 0; r < e.length; r += 1) if (e[r].target === t) return r;
        return - 1
      }
      r.ResizeObserver = s;
      var f,
      v = function (e) {
        o.forEach(function (t) {
          t.$$activeTargets = [
          ],
          t.$$skippedTargets = [
          ],
          t.$$observationTargets.forEach(function (r) {
            r.isActive() && (h(r.target) > e ? t.$$activeTargets.push(r)  : t.$$skippedTargets.push(r))
          })
        })
      },
      d = function () {
        var e = 1 / 0;
        return o.forEach(function (t) {
          if (t.$$activeTargets.length) {
            var r = [
            ];
            t.$$activeTargets.forEach(function (t) {
              var n = new i.ResizeObserverEntry(t.target);
              r.push(n),
              t.$$broadcastWidth = n.contentRect.width,
              t.$$broadcastHeight = n.contentRect.height;
              var o = h(t.target);
              o < e && (e = o)
            }),
            t.$$callback(r, t),
            t.$$activeTargets = [
            ]
          }
        }),
        e
      },
      h = function (e) {
        for (var t = 0; e.parentNode; ) e = e.parentNode,
        t += 1;
        return t
      },
      p = function () {
        var e,
        t = 0;
        for (v(t); o.some(function (e) {
          return !!e.$$activeTargets.length
        }); ) t = d(),
        v(t);
        o.some(function (e) {
          return !!e.$$skippedTargets.length
        }) && (e = new window.ErrorEvent('ResizeLoopError', {
          message: 'ResizeObserver loop completed with undelivered notifications.'
        }), window.dispatchEvent(e))
      },
      b = function () {
        f || g()
      },
      g = function e() {
        f = window.requestAnimationFrame(function () {
          p(),
          e()
        })
      },
      $ = function () {
        f && !o.some(function (e) {
          return !!e.$$observationTargets.length
        }) && (window.cancelAnimationFrame(f), f = void 0)
      };
      r.install = function () {
        return window.ResizeObserver = s
      }
    },
    {
      './ResizeObservation': 2,
      './ResizeObserverEntry': 4
    }
  ],
  4: [
    function (e, t, r) {
      'use strict';
      Object.defineProperty(r, '__esModule', {
        value: !0
      });
      var n = e('./ContentRect'),
      i = function () {
        return function (e) {
          this.target = e,
          this.contentRect = n.ContentRect(e)
        }
      }();
      r.ResizeObserverEntry = i
    },
    {
      './ContentRect': 1
    }
  ],
  5: [
    function (e, t, r) {
      'use strict';
      Object.defineProperty(r, '__esModule', {
        value: !0
      }),
      e('./ResizeObserver').install()
    },
    {
      './ResizeObserver': 3
    }
  ]
}, {
}, [
  5
]);