public byte[] getFooterHash(String hashName) {
		if (footerHashes.containsKey(hashName)) {
			return footerHashes.get(hashName);
		}

		return null;
	}
Get the value for the specified hash as stored in the footer or null if not
available. This value will not be tested for validity until the payload is
extracted.
<p>
<b>Note:</b> Only hash names specified in CartV1Constants.expectedHash (keys)
are supported.

@param hashName The name of the hash to be read
@return The hash value bytes or null
Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/cart/CartV1File.java