Feed Chooser RSS Blog Block for React

Yes. It writes the chosen feed's address to the clipboard through the catalog's Copy Button, swaps its icon for a check, and says "Feed address copied" in a polite status inside the button. If the browser refuses (a page not served over HTTPS), it shows a cross and says it could not copy.

Both the field and the window. The tab state is one value: the panel under the tabs shows that feed's address, and the drawn reader shows its sidebar selection and its three entries. Every feed has three entries, so the window never changes height.

No. It is artwork: a window frame, a sidebar and rows. The entries are real text with their fixed dates (plain rows, not a list or headings, since the window is a drawing that changes with the tab), and the frame and sidebar are hidden from assistive technology. Edit FEEDS to change the addresses and entries; the caption says they are examples.

It is a link. Point href at a feed: address or your feed URL and the visitor's default reader opens. Nothing is subscribed inside the page.

The copy comes first, with the tabs, the field and the button, then the window under a hairline with its sidebar hidden so the entries have the full width.

Yes. The split and the window mirror and dates are isolated with bdi. The feed address is code, so it always reads left to right.