One example of hard problem in UI Engineering: Accessibility. In github markdown editor, we can format code by wrapping with ``` . But after that, what happens

One example of hard problem in UI Engineering: Accessibility. In github markdown editor, we can format code by wrapping with ``` . But after that, what happens if we press Tab ? Should the code indent, or the focus move outside of the editor ? It's confusing and annoying currently to move the focus outside of editor.