IIRC there's an option to enable tracking protection in normal browsing on desktop. It's enabled by default in private browsing. (I can't check right now though - it's possible it's just an about:config option too.)

Firefox iOS (on iOS 11+) definitively offers those options, on Android it's private browsing only by default and I don't think there's an option to enable it in normal browsing.

In Firefox Developer edition on macOS there's no obvious way to add new blocklist sources in the UI. You can switch between two provided by Disconnect.me, and that's it.

Do you have version 57.0b3? It comes with two blocking lists.

I have 57.0b6. Looks like it's only enabled on Privacy mode like others have mentioned. Would LOVE to have this enabled on regular mode (even behind a flag). I'd totally switch to Firefox for most development if that worked.

Type `about:config` in the address bar.

Then type `privacy` in the search bar that appears.

Look for `privacy.trackingprotection.ui.enabled` and double click it.

I think that will turn it on everywhere.