Files treated differently. Why?

file 1: https://textfiles.meulie.net/survival/tenherbs.txt
file 2: https://textfiles.meulie.net/survival/1hrrads.txt

When trying to open file 1 in a browser, I get prompted to download it. When trying to open file 2, it displays in the browser.

I've checked both with Redbot, and can't see any difference:
file 1: https://redbot.org/?uri=https%3A%2F%2Ftextfiles.meulie.net%2Fsurvival%2Ftenherbs.txt
file 2: https://redbot.org/?uri=https%3A%2F%2Ftextfiles.meulie.net%2Fsurvival%2F1hrrads.txt

No special config in the site-config either. What can explain this difference in treatment?

Regards,
Evert