Semantics(header:true) is currently mapped to UIAccessibilityTraitHeader on iOS, https://developer.apple.com/documentation/uikit/uiaccessibilitytraitheader?language=objc.
Android Accessibility framework provides a similar affordance called "accessibility heading", https://developer.android.com/reference/android/view/accessibility/AccessibilityNodeInfo.html#setHeading(boolean).
This is a feature request to implement corresponding semantics for Android to bring parity support for accessibility headings on both platforms.

/CC goderbauer