This is a fork of the Blockly library which is modified for use inside Scratchity.
This "Blockly" however is forked from the "Open Roberta Blockly" instead of the main blockly because the "Open Roberta" one has some nice features that were also needed. (E.g. variables have types + nice color coding for types, there is a section to declare variables, nice flat styling, ...)
Google's Blockly is a web-based, visual programming editor. Users can drag blocks together to build programs. All code is free and open source.
The project page is https://developers.google.com/blockly/