Match the mime type of the search suggestions example to the Suggestions extension specification.

[Standard8]

Currently the MIME type of the search suggestions example in the URL element section gives a MIME type of "application/json".

It would be better if this was "application/x-suggestions+json" as that would match the Suggestions extension.

Reported by feluchs via https://bugzilla.mozilla.org/show_bug.cgi?id=1425827

[dewitt]

Thanks for the pull request! I'm inclined to merge it, but let's have the discussion here first, just to make sure we cover everything.

Obviously this one is tricky, since the examples and specs should match the browser's real-world behavior ("application/x-suggestions+json"), but I believe most people would now say that "application/json" is more correct (RFC 7159), since people don't seem to be sub-mimetyping JSON payloads. (Back then, who knew where things were going to head.)

In fact, it might be that the only place "application/x-suggestions+json" is used is the OpenSearch suggestions extension spec. Indeed, a Google search seems to confirm that.

Also, it would be a breaking change, presumably putting existing code out of recommendation with the existing, 12-year-old main spec (but in compliance with the equally-old extension's spec). Probably not a huge deal, but worth noting.

As a way of splitting the difference, do you think there any chance Firefox would be able to accept both types? In which case, maybe we should revise the Suggestions extension spec to use "application/json", and add a comment about the historical way of doing things.

If Firefox can't change (and I'm not suggesting I expect it to, since this is probably long dormant code there, too) then it might be better to go forward with this patch after all.

Did I get anything wrong in that summary? Thoughts about how to proceed?

[Standard8]

Sorry for the delay in responding. Just a quick update, we're currently discussing the possibility of supporting both MIME types. I'll update again when we know more.

[Standard8]

We've posted an intent to ship: https://groups.google.com/forum/#!topic/mozilla.dev.platform/mlNx35Xjw0U for FF 63. We'll give it a few days for feedback, then look at adding it to nightly builds.

[Standard8]

This has now been added to Firefox 63 (it'll appear in beta in a few days): https://bugzilla.mozilla.org/show_bug.cgi?id=1425827

So we don't need this PR now, though at some stage it'd be nice to tidy up the suggestions extension to clarify the allowed types.