LSP refers to the Language Server Protocol, a standardized protocol designed to provide real time source code information for a given code base; tree-sitter is

LSP refers to the Language Server Protocol, a standardized protocol designed to provide real time source code information for a given code base; tree-sitter is parser design to create a real time syntax tree for a given source file. No doubt the OP is suggesting the use of an Emacs plug-in based on those newer technologies.