It's now possible to instruct browsers to save files instead of viewing them inline

The default behavior for all media downloads is to display the file contents in the browser where possible, then fall back to a regular file download. Now it is possible to force Content-Disposition: attachment by setting the query parameter dl=1 on the media entity's canonical path.

For example:

https://www.example.org/media/NN will result in the default behavior where an inline content disposition is preferred, but will fall back to a regular download if inline display is not possible.

https://www.example.org/media/NN?dl=1 will force the file to be saved to disk by the browser.

Development notes:

1. Any value other than dl=1 is currently ignored, but may see future use.
2. Backward compatibility is not guaranteed for any values where dl does not equal 1.
3. As a result, the only two supported request scenarios are when dl is not present, or dl=1.