The GNOME Foundation has recently been targeted by a patent troll (Rothschild Patent Imaging, LLC) for developing the Shotwell image viewer software, which has been in use for over 10 years.
We don't know the details of their case, but the idea of patenting an image viewer, and then suing the developers of 10-year-old open source software is completely outrageous.
Rothschild "offered" to allow GNOME to settle the suit for a high five figure amount (presumably USD), however GNOME decided not to play their game and instead go the more expensive route to have the case dismissed completely and raise a counterclaim in an attempt to discourage future patent trolls from baselessly hassling open source software developers.
As HDRI Haven is built on the shoulders of dozens of open source software, and all our HDRIs are released in a similar spirit (public domain), I'd hate to see this become a trend.
If you'd like to read up more about this issue: