But Apple does not allow third-party rendering engines on iOS, so Mozilla and other vendors have to build theirs on top of Webkit.
Google has made iOS code available in Chromium repository by supporting both Blink and Webkit. See [1]. Not sure about Mozilla.
Note you cannot read the blog article without turning off Focus as content blocker (but you don’t have to quit (see 2).
Also, when I was young I was very confused which rendering engine was used because the user-agent header in HTTP was such a piece of mess (thanks to the browser war in the 90s). You are going to see webkit, blink, mozilla and NT in there.
[1]: https://blog.chromium.org/2017/01/open-sourcing-chrome-on-io...
That said, I believe they do intend to switch to Gecko at some time in the future, but no idea how soon that would be...
EDIT: I say "google, apple, whatever", but I should clarify. There's this talking point on HN that Apple is so good for user's privacy. It's not, hence "google, apple, whatever".
Could you clarify what is the third party that Mozilla is sending analytics to?
Mozilla has a promise from Google that Google will not use this data for their own analysis. If you do not trust Google to honor this agreement, Mozilla employees said on a GitHub issue about this, you should stop using Mozilla products.
Firefox sending my data to a marketing company should not be on by default... Heck, it should not even be an option.
Mozilla is not even sneaky about it. On the Google Play download page, the privacy notice for the app tells you that optional usage tracking is on by dafault. https://support.mozilla.org/en-US/kb/focus#w_privacy
Perhaps you should read the privacy notices for apps if you are concerned? It seems perfectly acceptable to me.