• CEP 1xx - User experience
• CEP 2xx - Frontend
• CEP 3xx - Pure Python support
• CEP 4xx - Support for wrapping existing C/C++/Fortran/... libraries
• CEP 5xx - Cython language features
• CEP 6xx - Optimizations
• CEP 8xx - Backends
• CEP 9xx - Cython internals
• CEP 10xx - Cross-project specifications
• Exploring new concepts