WAGO lever nuts are typically used for household electrical - often in place of wire nuts.

They can also be used for splicing or splitting audio lines.

Here is a simple distribution box with WAGO components mounted on a DIN rail:

The WAGO 221-413 lever nuts are mounted on a 221-500 mounting carrier which is mounted in turn on a 222-510 angled DIN-rail adapter.

The end stops on the DIN rail are "DIN Rail Terminal Blocks End Stopper Bracket" (Amazon).