Visual Common Works Registration Validator
This tool validates CWR 2.1/2.2/3.0 files and outputs result as colored HTML with additional mouse-over information on all fields.
It was released in 2017 as a free tool, sparking the revolution of independent CWR-capable tools. And sustained it since. There is a YouTube video playlist about this tool.
Free (demo) version below only validates and highlights the first transaction, and only accepts CWR 2.1 files.
The yearly subscription for the full tool is €400 per user.
If you are just interested in syntax highlighting, without validation, use Visual CWR, a completely free-to-use tool.