Why is 的 used in 你想要什么喝的吗? 你想要什么喝的吗?

I've seen 的 used after a verb like this in other sentences. The only thing I could find about 的 after a verb was when it's used with 是.
Here, you could think that "的" converts a verb (i.e. "喝"/drink) into a noun, i.e. something for drinking.

But notice the "的" after "是" is different, it is more of an interjection, and does not have additional meaning.