"Find Inline" feature in Safari

[zv6000]

Would anyone be aware of how Safari's find inline (where you type a word into the find banner below the bookmarks bar, and Safari shows the number of matches by brightly highlighting the results while dimming the page) feature works???

I'm interested in learning about the foundational / core / underlying construction of this highlight-dim feature.

Any help would be greatly appreciated.

Thanks in advance.