It needs more docs. Open an issue to put it in the queue. It’s the same as Modelica though:
- Equality variables connect by making values equal. For example, connecting pins in an electrical circuit makes the voltages equal at the junction.
- Flow variables connect by making the sum zero. For example, connecting pins in an electrical circuit makes the current sum to zero at the junction.
- Stream connectors are for fluids. See 15 Stream Connectors‣ Modelica® Language Specification version 3.7-dev and https://build.openmodelica.org/Documentation/Modelica%204.0.0/Resources/Documentation/Fluid/Stream-Connectors-Overview-Rationale.pdf .
Fluids are hard man.