Interesting project, writing a useful PHP extension is an every web developer's dream.

However, the licence choice is weird. It's really asking to be MIT. Any company bigger than 2 people pays attention to that. Most web projects are proprietary. GPL‑v3-or-later is not appropriate for proprietary/closed-source.

Also, the README is lacking a nicely looking comparison chart, motivating people why they should use your project instead of just running grep in shell_exec. I'm very unlikely to run the benchmarking scripts myself. You have to convince me why your project is better than the established industry practice.