Why is resource id different at runtime than in editor?

Question

Using Android Studio 4.1

I have a layout with a toolbar. I refer to the toolbar resource id in Java as R.id.mytoolbar for example. In the Java editor, when I hover over the R.id.mytoolbar reference, the popup displays something like:

public static final int mytoolbar = 1000067

I am wondering what that means, particularly the value 1000067. At runtime, the value of R.id.mytoolbar is a different integer, in particular: 2131296664 (hex 7f090198).