https://www.apkmirror.com/apk/mozilla/firefox-nightly-for-developers/firefox-nightly-for-developers-nightly-200630-0601-release/firefox-nightly-for-developers-nightly-200630-0601-2-android-apk-download/
Just downloaded the Firefox Nightly for Developers Nightly 200630 06:01 (Early Access) (x86_64) (Android 5.0+) APK from @APKMirror