Problem is that if the browser doesn't support viewing of the file, then both links will cause a download, which can be confusing to the user. I think we need a way to see if a MIME type of a file is supported by the browser (including its plugins.)

so would the browser be enforcing that? Or the server?

Because both options are unacceptable.

Why are both unacceptable? Server enforcing downloading/viewing measn the user couldn't override its choice, but providing both links avoids that issue.

If the browser presented both choices, it wouldn't be able to distinguish by situation, so either it would hide downloading inappropriately, or it would present it inappropriately.

If the server was in charge, then most websites would screw it up through incompetence or malice.

Two links for every link, or have the server (an entity who doesn't necessarily have the users interest in mind) having more control over what the user can do with the content it sends.

Both options suck.

To be fair? I got responses in favor of both options.

The browser is enforcing that, unless you tell it not to, like you always can with a browser.

At least it's not Javascript.

The page author would be forcing it?

I think the best way is for the designer to include both options. Don't leave it up to the browser.

Good idea, and one that more and more sites are implementing these days.