Out of curiosity, how are Konqueror and Falkon relates to the big three?
Their websites say they use KHTML or KDEWebkit (Konqueror) or QtWebEngine (falkon). Are these downstream adaptations of apple-WebKit?
Judging by the QtWebEngine page, it doesn't explicitly say it, but I think it is based on chromium.
Konqueror is a bit harder to figure out. Maybe QtWebKit. Is this also Chromium?