Feature request: download EPUB when available
Some journals like SAGE journals make EPUBs available for download (e.g. https://journals.sagepub.com/doi/epub/10.1177/1357633X16671407). EPUB is a superior format for digital reading and the scientific world is increasingly adopting, so it just makes sense to have a functionality that allows downloading EPUBs whenever available.
https://journals.sagepub.com/connected/sgo
Most major publishers have RSS feeds of their journal contents and many also provide feeds for ahead-of-print ePubs.
You can use Zotero to access these RSS feeds, read the abstract, and optionally import the items into your Zotero library / collection. If the journal is open-access or if you are affiliated with an institution that has a subscription, you can capture the full-text PDF of the articles into Zotero.