Devtools are also in standard firefox. The developer edition just includes new features that haven't yet made it to the current release. The chrome analog is Chrome Dev (https://www.google.com/chrome/dev/)

Firefox: Nightly -> Developer -> Beta -> Stable -> Extended Support Release

Chrome: Canary -> Dev -> Beta -> Stable

Firefox is actually Nightly->Beta->Stable->ESR, where Developer Edition is a differently configured build of Beta.