Worked on enhancing registry performance in the elixir-lang/elixir repository by migrating the registry key storage from an ETS duplicate_bag to an ordered_set. This change enabled more efficient key-based lookups and improved scalability for large registries. The approach involved adapting match specifications and reserved atom key handling to align with the new ordered_set structure, as well as updating initialization and runtime state to reflect the ordered nature of keys. The work focused on the {:duplicate, :key} entry, leveraging Elixir and ETS for backend development, and resulted in a more performant and maintainable registry implementation for the project.