Reason

From Joe Kelley at the NRC:

I am working on a 7-cell model that uses the GapHeatTransfer BC for every pair of sidesets as was done for the "reference" calculation in the extended scope task.

In that calculation, there were only two axial regions in the meshing-tools script, the support plate and everything else.

we should add .ipynb to the gitignore - notebooks are out-of-scope for this repo. In the past we have had some notebooks be committed which adds a large volume of code to the log that is later removed

We currently have a quite low test coverage in the PETSc radial-basis function mapping.

To be more precise, we only test the Tree preallocation strategy. All remaining strategies Compute, Save, Estimate, None are not tested at all.

See the file on [CodeCov](https://codecov.io/gh/precice/prec

couping-scheme:multi is a rather complicated feature of preCICE for which we currently over no real example. Documentation entry.
To create one could be simple though: A channel flow with two flaps or two channel flows separated by an elastic membrane would do the job.
Could also be a nice ad