A semantic nitpick that is totally irrelevant. Most people on this website usually mean Gecko when they say they want to use Firefox, Blink when they say Chrome, etc.
You and I both know the headline means allowing other rendering engines.
You and I both know the headline means allowing other rendering engines.
Building a general purpose web browser is one of the most challanging software development projects. This may not be the case if one is cloning Chromium/Firefox where you get both the rendering angine and the browser app for free. If you are using WebKit, you are writing the browser application from scratch.
But we are not a good example. Take Firefox or Chrome on iOS, teams with hundreds of engineers. They are terrible mobile browsers. They feel completely out of place on an iPhone. Not because WebKit is bad, but because building a good, native, iOS browser is incredibly hard.
To bring it back to Kagi, if I'm reading your FAQ correctly for instance, you would not be able to support firefox/chrome extensions on iOS since you had to fork Webkit. Now imagine you are a browser with over a decade of use and features that now has to target a static other engine. How great of an experience do you really think you are going to get out of that?