You need to select the subscription at the Sidebar and the by secondary clicking (two finger, ctrl+click or the small gear icon at the bottom) you can access the context menu. You need to click on "Copy URL to clipboard".

rockysandstudio.com
Category: News, Feedly, Feedbin, RSS
Compatibility: MAC OS X Yosemite, El Capitan
Leaf: News Reader for Mac OS X (Yosemite, El Capitan)

Leaf is an amazing news reader for Mac OS X (Yosemite, El Capitan). Read, share, star and search news from all of your favourite websites by using a clean, intuitive, OS X Yosemite, El Capitan-style next generation interface. Leaf is supported feedly and feedbin. Feedly App for Mac OS X, Feedbin App for Mac OS X