Write a canonical answer for end users about Remote Settings changing browser settings in the background

[mostlygeek]

From time to time people misunderstand Remote Settings and may jump to conclusions. From time to time we may misunderstand remote-settings ourselves and also give out inaccurate information.

For example:

• https://news.ycombinator.com/item?id=29921274
• https://lobste.rs/s/zcjtv2/1749908_infinite_loop_http3_hangs_socket#c_gp6xbx

I think it would be useful to write an official blurb on what remote settings is. This blurb should be easy to share to help users understand its purpose more clearly and accurately.

A few things to touch on (off the top of my head):

1. It is a bespoke data delivery service for Mozilla and Firefox. It's more of a postal service, delivering data vs changing your browser's settings.
2. The types of data being sent through it varies from Example A ... Example B (blocklists, crlite, etc). You can inspect it yourself at https://firefox.settings.services.mozilla.com/v1/buckets/main/collections
3. It does not change preferences, that's Normandy. However, we do deliver Normandy recipes. Would be beneficial to link to more information about Normandy as well. Make sure we speak with @mythmon to get this right. Maybe it would be good to point out that we change the default values, user set prefs always win. (is this accurate?)
4. Disabling RS is not recommended. You'll lose out on security updates, patches, etc. (put extra effort into accurate and clear wording here.)
5. (anything else?)

We'll likely need to include marketing, legal, product engineering's feedback for the blurb to make sure we get the messaging right.

[mythmon]

It does not change preferences, that's Normandy. However, we do deliver Normandy recipes. Would be beneficial to link to more information about Normandy as well. Make sure we speak with @mythmon to get this right. Maybe it would be good to point out that we change the default values, user set prefs always win. (is this accurate?)

I'll be happy to review the proposed language. Please also include @jaredlockhart for Nimbus, which also uses Remote Settings, and although it doesn't change preferences, it does remotely change the behavior of the browser. Technically, Normandy has the capability to overwrite user-set preferences temporarily (they get set back at the end of the experiment). In practice though that experiment technique is discouraged and I don't think it has ever been used outside of internal-only tests.

[mostlygeek]

@leplatrem blog post on the History of Remote Settings is a useful resource to link to. Particularly on why we built it and how it evolved into the system it is today.