During Marvel’s Comic-Con movies panel, the lucky people inside the Hall H got to see a mockumentary about how Thor spent his time during Captain America: Civil War. One of the things he did was set up a conspiracy theory wall, like all good detectives do. Thanks to director Taika Waititi, everyone can now see the Thanos part of the wall.
Source: io9 – Everything We Know About Thanos in the Marvel Universe, According to Thor