Is 111 a valid HTML id attribute or are document.querySelector() and document.querySelectorAll() correctly throwing syntax errors?

Given

const  div = document.createElement("div");

div.id = 111;

document.body.appendChild(div);

try {
  console.log(document.querySelector("#111"));
} catch(e) {
  console.error(e); 

  /* 
     Chromium:

     DOMException: Failed to execute 'querySelector' on 'Document':
     '#111' is not a valid selector.

     Firefox
     SyntaxError: '#111' is not a valid selector

  */
}

try {
  console.log(document.querySelectorAll("#111"));
} catch(e) {
  console.error(e); 

  /* 
     Chromium:

     DOMException: Failed to execute 'querySelector' on 'Document':
     '#111' is not a valid selector.

     Firefox
     SyntaxError: '#111' is not a valid selector

  */
}

however, document.getElementById() returns the element

const  div = document.createElement("div");

div.id = 111;

document.body.appendChild(div);

try {
  console.log(document.getElementById("111"));
} catch(e) {
  console.error(e); 
}

References:

6.2 SGML basic types

ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").

7.5.2 Element identifiers: the id and class attributes

Attribute definitions

id = name [CS] This attribute assigns a name to an element. This name must be unique in a document.

DOM - Living Standard

While this specification defines requirements for class, id, and slot attributes on any element, it makes no claims as to whether using them is conforming or not.

HTML - Living Standard

The id attribute specifies its element's unique identifier (ID).

There are no other restrictions on what form an ID can take; in particular, IDs can consist of just digits, start with a digit, start with an underscore, consist of just punctuation, etc.