There are 2 repositories under concrete-syntax-trees topic.
Parse Wolfram Language source code as abstract syntax trees (ASTs) or concrete syntax trees (CSTs)
A portable Common Lisp reader that is highly customizable, can recover from errors and can return concrete syntax trees
Parser for the Nix Expressions Language
Meta Representation for building Java programs to analyze, generate, refactor & run Java source code
Configuration file for Emacs 30.0.5 with tree-sitter and combobulate for macOS
AST transformations as an example of compile-time metaprogramming in groovy.
A project in which given a file with treebank bracket notation it will verify there are no syntax errors and then it will generate an abstract syntax tree using Coco/R