This page was opened directly (file://) — browsers block fetch() of local files that way, so it can't auto-read a sibling results file. Serve this folder over HTTP instead, from the same directory as this file and :
bunx serve . # or: npx serve . / python3 -m http.server 8000
Then open the printed http://localhost:... URL instead of double-clicking this file. Override the auto-load filename with ?file=name.jsonl in the URL. The button above still works over plain file://, for a one-off manual pick.