How can a variable in Javascript be a function, but not be able to be called?

I am currently investigating a website, and have found a curious thing. If I find a PNACL embed element in the developer console, and evaluate it in the Chrome dev console, it logs > anonymous(), with an arrow next to it that reveals it's an ordinary HTML element. However, typeof temp1 (the variable name) returns function, but calling it throws

Uncaught TypeError: temp1 is not a function
    at <anonymous>:1:1

and calling toString() returns "[object HTMLEmbedElement]". What does > anonymous() mean, and how can a Javascript variable be a function but uncallable?

MCVE:
FF

var el=document.createElement("embed"); //<embed>
typeof el;// "function"
el.toString(); //"[object HTMLEmbedElement]"
el(); // [Exception... "Component is not available"  nsresult: "0x80040111 (NS_ERROR_NOT_AVAILABLE)"  location: "JS frame :: debugger eval code :: <TOP_LEVEL> :: line 1"  data: no]

Chrome

var el=document.createElement("embed"); // anonymous()
typeof el;// "function"
el.toString(); //"[object HTMLEmbedElement]"
el(); //undefined

This is a known bug, I did filed a year ago.

Affected elements :

• HTMLAllCollection
• NPObject(?)
• HTMLObjectElement
• HTMLEmbedElement

Answer from chromium team :

External users have not complained about it, so I'm thinking of Archiving it.

_{Damn I'm an "external user"...}

Current status : Archived

Causes :

These elements have a [Call] internal method, hence according to EcmaScript, typeof must return 'function'. _{(And this makes the bug a specification one rather than an implementation one...)}