There will be a flat 20p deposit on all eligible plastic and metal drinks containers. These deposits can be retrieved by returning containers to collection points at supermarkets.
The Welsh government want this to be devolved to them: https://exchangeforchange.co.uk/news/welsh-government-decision-on-exchange-for-changes-dmo-application/
Beer used to be distributed in earthen jugs, which remained brewery property and had to be returned. Same for milk bottles. The idea of buying the packaging as well as the product is fairly new.
An earthen jug of ale is definitely something I can get behind