Video tl;dr:<p>Psychtoolbox is a popular open source tool for creating vision and neuroscience experiments. As typical of open source projects, the project mostly runs by a single, underpaid developer's time (Mario Kleiner). They tried to be funded through "support membership" donations, it did not work, and now they announce that a paid license will be required for running their compiled binaries "on some operations systems".<p>The relevant part where they describe the funding situation of the project starts around 6:00 as in <a href="https://youtu.be/05gpkP_EMoc?t=363" rel="nofollow">https://youtu.be/05gpkP_EMoc?t=363</a> (sorry for messing up the link in the post)