Add loyalty guidance for facilitating users switching UAs (#28)

* Add loyalty guidance for users switching UAs

Closes #5

* Apply suggestion from @jyasskin

Co-authored-by: Jeffrey Yasskin <[email protected]>

* Clarify credentials and OS-stored passkeys re switching UA

* Change passkey to credentials example for OS storage

Co-authored-by: Marcos Cáceres <[email protected]>

* Clarify relying on OS stored credentials and reuse

Co-authored-by: Jeffrey Yasskin <[email protected]>

* Editorial on relying on and access for OS stored credentials

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Co-authored-by: Jeffrey Yasskin <[email protected]>
Co-authored-by: Marcos Cáceres <[email protected]>

Author: 3 people

index.bs

@@ -153,6 +153,11 @@ A user agent can also help its user
 make a credible commitment to a page in order to get that page's services,
 and it's not disloyal to maintain that commitment after getting the services.
 
+A user agent must not obstruct its users from switching to another user agent.
+For example, it must not block access to, export, or store user data in ways that prevent portability.
+This includes identity information, bookmarks, history, passwords, and credentials such as passkeys.
+If the user agent relies on the underlying <abbr title="Operating System">OS</abbr> to store credentials,
+there needs to be a way for users to allow other user agents to access those credentials.
 
 <section class="non-normative">