The documents your cards produced, and the shells you work in beside them. Both sit under WORKSPACE in the sidebar.
A file list per project of everything worth keeping: research reports, PDFs, web pages, images, data files, and the files attached when a card was captured. It is one folder per project and one per card inside it, with the columns NAME, KIND, FROM CARD and SIZE, and FROM CARD opens the card that produced the file. Attachments sit in the same card folder as the rest, drawn faint and sorted last, so the references a card produced stand apart from what you handed it.
A research card can deliver its outcome as a PDF filed in the library, a web page, or a section on the card: pick it under OUTPUT when you capture the card, or leave it on Auto. An outcome written on the card stays on the card; the library lists only files.
Not in 0.3.0. The library is built and arrives with the next alpha release.
Terminals in a grid of one, two, four, six or nine slots (2×2 by default), one layout for every tab. An empty slot opens a free shell in a project or a card's session. ⇄ moves a terminal to another tab, and closing a tab moves its terminals into free slots elsewhere; when they do not all fit, Grid asks first and closes the ones that do not. The focused card sits beside the grid with its summary and tasks, and with no card focused that pane lists the open cards.