The new fun and fancy feature of Activities is being able to link files and folders to activities by right-clicking them in Dolphin, Konqueror, Folder View. You can see what it looks like in the screenshots.
The first screenshot shows the menu for a single file, while the second shows it for a multi-item selection.
What’s the point?
Currently, this doesn’t do much – you can show the linked files on your desktop if you set your desktop layout to be contour (not the whole Plasma Active, but only the widget layout).
And soon, I’m planning to also have a KIO implemented so that you can browse all the linked files by browsing activities://something/…