India has had vegetarian burgers for years, in fact, most people order these veg burgers because they don't eat meat ( culture / religion ). Ive never eaten meat, but I really love burgers.
Also, that's just the server project. There are also clients like the mobile app and the terminal app, which have a whole new set of active contributors.
Apart from a user, I am also a contributor to the Zulip project, for the last ~7 months.
The community is very helpful and for getting started with open source development, I can't recommend a better place. You get really high quality code reviews, get to participate in meaningful discussions on features and the development goals of the project, and developers constantly share lots of knowledge in streams like #learning about software development, tech, git, best practices and so on.
Also, the documentation is very detailed and the codebase is very high quality. It's really easy to get started.
Solving problems during contests is a battle against time. You cant waste time compiling and checking if your solution is correct, and incorrect solutions have penalties.