[Boltgolt]

The web version of Duolingo used to have detailed explanations for each lesson that explained a lot of grammar, they seems to have disappeared recently

[nyordanov]

They are still there, but they've changed the UI and removed the lesson permalinks, so it's now harder to both find and use these explanations.

Click on a lesson's circle and there is now a lightbulb icon which opens the detailed lesson.