Emacs 29 features tree-sitter support, a powerful parsing library that allows more accurate syntax highlighting, indentation, and editing. However, it is an optional feature that requires users to compile Emacs from source or wait for someone else to compile it. Installing and configuring tree-sitter is a bit cumbersome and involves installing language grammars separately, but it is worth the effort for the benefits it provides. Using tree-sitter involves activating the new major modes manually, and users may need to duplicate or change mode hooks and customize font lock faces. Overall, tree-sitter is a valuable addition to Emacs for those willing to put in the effort to use it.
https://www.masteringemacs.org/article/how-to-get-started-tree-sitter