https://www.theverge.com/2018/6/28/17513036/google-kaios-investment-feature-phones-firefox-os-apps-services-strategy

Google is investing $22 million into KaiOS, the feature phone operating system that has risen from the ashes of Mozilla’s Firefox OS. While Google rules the smartphone world with Android, KaiOS is slowly emerging as a popular choice for feature phones, particularly in emerging markets. KaiOS started last year as a forked version of Firefox OS, and the operating system ships on some Nokia-branded feature phones like the Nokia 3310 and Nokia 8110. Devices from TCL and Micromax are also powered by KaiOS.

Google’s investment might seem odd given its Android dominance, and its efforts with Android Go, but it’s clearly strategic. “Google and KaiOS have also agreed to work together to make the Google Assistant, Google Maps, YouTube, and Google Search available to KaiOS users,” says KaiOS CEO Sebastien Codeville. KaiOS itself is web-based, designed for developers to use HTML5, Javascript, and CSS for apps. That makes it easy for Google to get these apps running on KaiOS, and strategically ensure feature phones are using Google’s services and not competitors.