You can get downzaps by installing the browser extension that I created (it'll give you a permanent downzaps button in Stacker.news). The botom of this post has instructions on how to install the extension - #1473885.

The extension also has a cool new feature, which is that downzaps are high-lighted in red (otherwise it's 3 clicks to see each item's downzaps, which is a pain).

Or, you can just regularly go to this link, for the top weekly downzaps.
https://stacker.news/top/posts/week?by=downsats

under TOP