This is a smooth term. Specifically a penalized thin plate regression spline (if I remember correctly that is the default). You can learn a lot about splines from Gavin Simpson’s blog and this excellent post by Tristan Mahr about splines as they are implemented in brms.
The code that you ran fit a smooth term to each ‘type’.
The coefficients of the smooth terms are not very interpretable. See here and here.
You can make predictions for different values of ‘node_num2’ and different levels of ‘type’ and ‘location’. You can also estimate the first derivative of the spline via finite differences if you would like to find the slope of the spline, see here for the concept and here for what you will need from brms, posterior_smooths.
If this isn’t acceptable, then maybe you should think about the relationship between ‘node_length’ and ‘node_num2’ and come up with a more generative explanation that you could fit using the non-linear syntax in brms.