Suggestions for Cssyntax

The following packages have something in common with the package Cssyntax. The packages are ordered in decreasing similarity.

Package l3build: A testing and building system for (La)TeX
Package starray: A structured array (of properties) based on expl3
Package sdaps: LaTeX support files for SDAPS
Package verifycommand: Verifies definitions are unchanged, such as before patching
Package styledcmd: Handling multiple versions of user-defined macros
Package ccool: A key-value document command parser
Package ltxnew: A simple means of creating commands
Package xoptarg: Expandable macros that take an optional argument
Package xnewcommand: Define \global and \protected commands with \newcommand
Package optparams: Macros with multiple optional parameters
Package cdcmd: Expandable conditional commands for LaTeX
Package lambdax: Use Lambda expression within LaTeX
Package mathcommand: \newcommand-like commands for defining math macros
Package langsci-affiliations: Collect and order authors and affiliations
Package xfp: Interface to the LaTeX3 floating point unit
Package xparse: A generic document command parser
Package inlinedef: Inline expansions within definitions
Package xtemplate: A high-level interface for declaring document commands
Package letltxmacro: Let assignment for LaTeX macros
Package causalmodels: Notation macros for causal graphical models
Package defstring: Define macros as verbatim macros
Package getoptk: Define macros with sophisticated options
Package latex-dependency-grapher: Visualize the dependencies of LaTeX files
Package makedtx: Perl script to help generate dtx and ins files
Package texpack: Create documented LaTeX classes, packages and docs in a Unix environment
Package sty2dtx: Create a .dtx file from a .sty file
Package interfaces: Set parameters for other packages, conveniently
Package tracklang: Language and dialect tracker
Package dvisvgm-def: Colour and Graphics support for dvisvgm
Package dvipdfmx-def: Configuration file for dvipdfmx graphics
Package pdftex-def: Colour and Graphics support for pdfTeX