I am new to GSOC. I have gone through the guidelines and understood everything. I learned that contribution is necessary before sending a proposal to a mentor. The wiki page seems confusing to me. Can anyone guide me how can I contribute to existing issues that is already out there or can I just directly send a proposal stating my approach?
We also require for all projects that you familiarize yourself with the software you want to work on. By the time you hand in your project proposal, you should have set up a working development environment and started to make a few simple changes to things that bother you. This part is not optional!
so I would head to Nominatim project page, find something to improve (say, simplest possible thing on the issue tracker - if you encounter another problem not yet reported on the issue tracker that is in scope of Nominatim and you want to fix it - then create a new issue)
or at least play around with the project, set up development environment, import small area
maybe you can contribute improvement to a setup documentation and help other newbies?
disclaimer: you should follow rules of the specific project, in this case of Nominatim. If all your contribution would be copy-pasting into and from LLM tool such as ChatGPT or running Claude Code then it is almost certainly not productive.