I am using papyrus-theme by Hugo Sereno Ferreira for my blog which is open source software licensed under Creative Commons (CC) license. I also modified it slightly to use Markdeep which has capabiity to convert ASCII diagrams into SVG diagrams. Markdeep is open source software licensed under BSD. Copy of license is located in _includes/markdeep_diagram/README.md. You are bound by it when using Markdeep.