How Would You Validate a Browser Highlighter That Finds Hidden Matches?

I am finishing building Highlighter Extension to handle cases Cmd‑F misses: hidden/truncated content and matches inside iframes. - Technically it uses CSS Custom Highlights, ancestor reveal + glow, and cross‑frame assist; tested on Jira/Confluence/Metabase. - I’m looking for advice on validation: which sites/tools would you use to pressure‑test this? What benchmarks matter most (latency, CPU, false positives)? - Happy to share internals or create repros based on suggestions.

P.S. Real smart folks would probably ask way earlier, than when I am already finishing certainly.