Comment by klibertp

I'm not going to blame you _too_ much, since I had similar suspicion, but you could have (as I did) just downloaded the .zip file and examined the contents. In the shareware version, some things are probably missing (I think not all themes are there), but otherwise it's just a bunch of PHP files, no obfuscation or anything. The markup language is configured in a text file, and the parser for that file is just next to it. The configuration is used for configuring the markup parser, which is also present. And so on. It's not open-source only if your definition of OSS is "has to have a Github page".