What is Library
Library stores all the stuff you've visited, downloaded, created, or saved on Arc. You can open Library from the bottom-left icon in your Sidebar, or by hitting Command-T and typing "Open Library".
Library has 5 sections:
Media: images, videos, screenshots, and captures taken throughout the web.
Downloads: files you've downloaded, including in-progress downloads.
Easels & Notes: Easels & Notes you've created or have shared access to.
Spaces: view and move around all your tabs across all Spaces.
Archived Tabs: search or browse closed and auto archived tabs across Spaces.
Access Recent Files
Hovering over the Library icon allows you to open and drag recent files. You can edit which items appear on hover by right clicking the Library icon and selecting / deselecting certain file types.