{
  single: { constructor: 1 },
  proto: Object.fromEntries([["__proto__", 2]]),
  several: { constructor: 3, prototype: 4 },
}

--

single:
{constructor:1}
{
  constructor: 1
}
{
  "/constructor": 1
}

proto:
{__proto__:2}
{
  __proto__: 2
}
{
  "/__proto__": 2
}

several:
{constructor:3,prototype:4}
{
  constructor: 3,
  prototype: 4
}
{
  "/constructor": 3,
  prototype: 4
}