Customers can choose who whether their money is given to the publishers or a charity. In this case, there will be three organizations to choose from: the United Nations Refugee Agency (UNHCR), the Comic Book Legal Defense Fund (CBLDF), and the Gaiman Foundation.
Here’s more from Gaiman’s blog post: “Refugees need help and support. Freedom of speech is under threat. I’ve brought back the original Humble Bundle of Gaiman extreme and collectible rarities, and I have added some brand new bits, including audio stories.” (via the Neil Gaiman Facebook page)