For those worried about what's going on with #Mozilla's new T&C for #Firefox and seeking alternatives to Blink-based browsers (aka Chrome-in-a-trenchcoat), consider helping @WebKitGTK (a port of @webkit), used by apps throughout the FreeDesktop.
#WebKit/WebKitGTK/WPE is effectively the only other mature/production-ready web engine you can use *today*, not many know that (see also https://github.com/Fyrd/caniuse/issues/6807).
I hedge my bets by simultaneously helping QA Firefox and Epiphany (WebKitGTK) for parity.