For now, you can drag the badge (usually the lock icon) at the left of the address field into the bookmarks sidebar and drop it where you want. If the bookmarks panel isn't open, you can hover over the heart icon in the sidebar for a second while in drag mode to open it and then continue dragging to the bookmarks panel.

You can also do this with links on a page. Drag up, continue dragging till you hover over the heart icon in the sidebar, wait for the bookmarks panel to open, continue dragging and then drop where you want.