Hi @promontis, the actual conversion routines are in the converters. Here’s where you can find them.
That’s because of the way we treat object models and their implementation (conversion). There’s some added info in our docs right here: Kits | Speckle Docs - long story short, they’re interchangeable, and not a hard dependency for Speckle itself. You can, if you want to, write your own Speckle Kit and use Speckle without our object model that we ship the plugins with by default.