This is the main Git repository for development of Psychtoolbox-3. It is meant for developers or alpha-testers only, not for regular users! Regular users should follow the download and update instructions on our Wiki at http://www.psychtoolbox.org. The data in this repository, the Psychtoolbox-3 distribution, is licensed by a mix of various free software and open source licenses. Most parts are licensed under MIT license, but a few bits are under other licenses. The file License.txt in the Psychtoolbox/ subfolder provides some overview. Some folders and files have individual licenses attached. Rough structure: managementtools/ - Contains scripts for management of the project. PsychSourceGL/ - Contains the C/C++ source code of almost all compiled binary mex files for GNU/Octave and Matlab and Python. PsychSourceGL/Cohorts/ - Source code of 3rd party (F)OSS libraries that we use, if required by their licenses, or patches against such libraries, if we had to make modifications that are not yet included in the upstream projects yet. Psychtoolbox/ - The end-user distribution with all compiled mex files and all M-Files, scripts, GLSL shaders etc. This is what gets downloaded by end-users by default. PsychPython/ - Code only used by Psychtoolbox Python support, e.g., test and demo .py scripts, helper libraries etc. from which a Python package is built.