Neovim
Vim fork from 2014 that modernised the codebase — Lua as the primary scripting language, async-driven, built-in LSP (since v0.5) and tree-sitter (since v0.6).
Started by Thiago de Arruda after a rejected refactoring patch to Vim. Today Neovim is more active than Vim — modern IDE features (autocomplete, go-to-definition, formatting) come out of the box via LSP rather than a plugin jungle.
Popular distros: LazyVim, NvChad, AstroNvim, LunarVim. Competitor: Vim 9 (has tried to catch up), VS Code (with Vim-mode), Helix (Rust-based alternative).