Ah! That link was so weird. The org site even contains this... interesting statement: "Opal Ruby to JavaScript Compiler It is source-to-source, making it fast

Ah! That link was so weird. The org site even contains this... interesting statement: "Opal Ruby to JavaScript Compiler It is source-to-source, making it fast as a runtime. Opal includes a casino comparison compiler (which can be run in any browser), a corelib and runtime implementation. The corelib/runtime is also very small." Casino comparison compiler?!