What about the person who start this itch.io project and their relation with UNRWA? When I was signed up, I was only led to a Google form that anybody can design.
Viewing post in Indie bundle for Palestinian Aid
She is a a relatively well known and trusted person within the community and has been very vocal about supporting these and other good causes LONG before the bundle became a thing. The creator of Itch has also posted about it and is in support of this bundle.
I have no personal relationship to her, but I have no reason to doubt her, so I am supporting it as much as I can.