Found a few ways in which the Braille problem with browsers could resurface. Fixed now.

internal/atspi/firefox_native_test.go

@@ -169,6 +169,29 @@ chromeFocus:
 				if !mixedLine.Expanded || strings.ContainsRune(mixedLine.Text, '\ufffc') || !strings.Contains(mixedLine.Text, "Inline message link") {
 					t.Fatalf("mixed braille line not expanded: %+v", mixedLine)
 				}
+				if err := adapter.SetDocumentCaretPosition(ctx, parent, event.Source.ID(), 0); err != nil {
+					t.Fatalf("place mixed-line caret: %v", err)
+				}
+				caretDeadline := time.NewTimer(3 * time.Second)
+			caretEvent:
+				for {
+					select {
+					case caret := <-adapter.Events():
+						if caret.Type != CaretEvent || caret.Source.ID() != parent.ID() {
+							continue
+						}
+						caretDeadline.Stop()
+						if caret.Source.BrailleLine != mixedLine.RawText || !strings.Contains(caret.Source.Text, "Inline message link") || strings.ContainsRune(caret.Source.Text, '\ufffc') {
+							t.Fatalf("caret repair lost embedded text: text=%q raw=%q", caret.Source.Text, caret.Source.BrailleLine)
+						}
+						break caretEvent
+					case <-caretDeadline.C:
+						t.Fatal("mixed-line caret event missing")
+					case <-ctx.Done():
+						caretDeadline.Stop()
+						t.Fatal(ctx.Err())
+					}
+				}
 				var paragraph ObjectReference
 				captured, err := page.Document(ctx, ref)
 				if err != nil {