It's funny and kinda frustrating how almost no one acknowledges the role #KDE played in forming the Web we see today.
It's KDE who created #KHTML, which was then in 2001 forked by Apple to create their #WebKit engine, and which was then used in #Chromium until version 28, when Google replaced WebKit with their own fork of it called #Blink.
And the only reason Apple forked KHTML and not #Gecko was because of Netscape's extensive and, as later admitted by Mozilla themselves,[1] often unnecessary usage of XUL/XPCOM, which Apple thought resulted in software bloat.[2]
So yes, almost every browser currenty existing uses an engine which is a direct or indirect descendant of KDE's KHTML.
And I'd bet my house that if there was no KHTML, and Apple were unhappy with Gecko, they'd probably create their own proprietary engine, and Google would follow.
So I'm kinda glad things ended up how they did, and there are no proprietary browser engines around.
Thanks KDE!
[1] - https://arstechnica.com/information-technology/2004/06/collins-interview/#page-2
[2] - https://web.archive.org/web/20121025015655/http://news.cnet.com/2100-1023-980492.html