https://developer.android.com/about/versions/13/features/copy-paste#sensitive-content

If nsITransferable.isPrivate is true, we may have to set EXTRA_IS_SENSITIVE when copying text to clipboard.

We should set EXTRA_IS_SENSITIVE for password or credit card data copied to the clipboard.

Tasks and enhancements should have severity N/A.

Unfortunately, Android JUnit test runner doesn't often get ClipbDescription.extras from clipboard service when running test runner. If test runner side fixes this issue, I will land/review this.

When nsITransferable.isPrivateData is true, such as coping password or
private mode, we should set EXTRA_IS_SENSITIVE to ClipData.

AndroidJunit test runner doesn't often get ClipDescription.extras
from clipboard service in test runner. So we cannot write a unit test
using AndroidJUnit test runner.

https://hg.mozilla.org/mozilla-central/rev/63d7060ba273

(In reply to Chris Peterson [:cpeterson] from comment #1)

We should set EXTRA_IS_SENSITIVE for password or credit card data copied to the clipboard.

Is there anything user facing worth nominating for a release note? (Process info)

Release Note Request (optional, but appreciated)
[Why is this notable]: When copying a text to clipboard on private browsing mode, Firefox handles it as sensitive context. So toast notification for clipboard is masked.
[Affects Firefox for Android]: Firefox 113
[Suggested wording]: When copying a text to clipboard on private browsing mode, Firefox handles it as sensitive context. So toast notification for clipboard is masked on Android 13 and higher.
[Links (documentation, blog post, etc)]:N/A

Thanks, added to the beta release notes.
Keeping the relnote-firefox flag as ? to keep it on the radar for inclusion in the final Fx133 release notes.

Added to the Fx133 release notes.
Available to preview on staging, please allow 30 minutes for the site to update.