Sooner or later you will get a pop-up asking if you want to download “index.html”.
As for the HTML stuff, yes, index.html is typically the default page served by a site. No web browser would mistake that as something to ask the user for download without a specifically modified .httpd or other site configuration, especially after properly displaying the page.
No, this is something else. And I do not know why I keep getting asked at various sites. Including cplusplus.com.
Just happened to me too, Duthomas, although it's the first time that I have seen it. Says something about "google syndication" and wants me to look in dropbox. I guess it's to do with the ads on this site and it's google's problem.
I was viewing the site on an (aged) iPad. I have yet to see any such problem from a PC.
I have had it happen on both my PC and my phone, but I tend to keep to a dozen or so sites, none of them untrustworthy. (Things like news and SO and here and the like. FB might be the culprit...)
I am using a fairly recent version of Vivaldi on my PC.
(I’m going to update my phone to use something other than Chrome, whose updates have been ticking me off lately.)
I wonder if Furry Guy’s suggestion is correct. I’ll clean my caches shortly.
Yep, seen that. None of those offer solutions to the current phenomenon.
My PC is Windows/Fedora and my phone is Android. Nothing Apple. (My iPad is currently retired — no sense in spending for internet connectivity on an extra device when I don’t need it.)
Alas.
[edit] Currently in the middle of something, so I haven’t cleaned my browser’s caches yet...