What does 'the key input state' mean in the Webdriver spec?

I've been trying to digest the Webdriver spec and its more friendly version. And I'm having trouble understanding what do these words mean (in the description of the 'Element Send Keys' command):

The key input state used for input may be cleared mid-way through "typing" by sending the null key, which is U+E000 (NULL)

I had several ideas of what it might mean, I mention some below as a sort of evidence of my 'prior research'*).

Could somebody, please, explain what does it mean and, if possible, give an example, preferably in JavaScript?

---

*Attempts to figure it out myself: I thought, one may skip calling releaseActions() if he previously pressed, say, the Shift key, like:

await browser.performActions([
  {
    type: 'key',
    id: 'key1',
    actions: [
      { type: 'keyDown', value: '\u0010', },
    ],
  },
]);
await browser.elementSendKeys(elemUUID, '\uE000ABC');

But no, the shift key was still pressed, when the elementSendKeys() was called.

Also I thought the null character clears text in the element, no, it doesn't.