Why is no text found?
The PDF is probably a scan: its letters are pixels, not stored characters. Use OCR a PDF to recognise them.
Reads the characters already stored in the PDF and restores them into visual line order. It does not guess headings or tables, and it says plainly when the pages are scans with no text layer.
Result
pages
The PDF is probably a scan: its letters are pixels, not stored characters. Use OCR a PDF to recognise them.
Plain text keeps lines and words only. Markdown also infers headings, lists, emphasis and tables from their appearance.
No. The text layer is read inside this browser tab and the .txt bytes are made here.