Why does website say the database is in JavaScript when it's in C#?

The website says event store website says “The open-source, functional database with Complex Event Processing in JavaScript.” but looking at the repo on Github it seems it is written in C#. What is that header supposed to mean?



The title is actually describing that it’s a functional database and in addition it has complex event processing in javascript.

The projections library for writing queries etc hosts v8 and your
queries are in JS