You’re browsing without an account. You can open your file and start reading or listening right away — it stays on your device, we don’t save it and it’ll disappear from the list when you refresh the page. With a free account (100 MB) files stay permanently, and the reader and player remember where you left off — on your phone too.
The reader and player only open when you click a file — none of their code loads before that. Cover from the file (EPUB) or page 1 (PDF); your reading and listening position is the same on computer and phone.