word usage - What is the meaning of "if anything"?

I do understand the meaning of "if anything" in the context. I can understand each word individually.

Here is the text:

In the past it was a common belief that snakes couldn't hear much, if anything, since they have no external ears and don't seem to respond much to noises. However, some scientific research refutes this common misconception.

I feel like the text is understandable without saying "if anything" so why does the writer put it in the text?

Answer

If anything is a an idiom used to describe a very small amount of something.

if anything (at all)
if (there is) anything

The price of the book, if anything, is a dollar.
That city, if anything, is a nice place to visit.

A similar phrase

if nothing else

has the same meaning as if (there is) anything

That city, if nothing else, is a nice place to visit.