Back in 2019, I submitted a GSOC proposal for Apertus. They wanted to add frame serving capability [1] to their RAW image processing software OpenCine [2]. Even though my proposal was rejected, I ended up learning a lot from their coding challenge [3] which was mandatory for submitting a proposal.
Reading research papers to understand Demosaicing [4], learning C++ coding guidelines, RAW file format, code reviews and feedback from Andrej and others at Apertus was really fun. At the time I was still a sophomore at college so I asked and made a ton of mistakes. Thanks Andrej [5] and team for being patient with so many of us! :)