1. htmlbuttonelement api: command

2. htmlbuttonelement api: commandforelement

3. htmlbuttonelement api: commandforelement: implicit anchor reference via `commandforelement`

4. htmlbuttonelement api: command: `request-close` value

5. html element: button: command

6. html element: button: commandfor

7. html element: button: commandfor: implicit anchor reference via `commandfor`

8. html element: button: command: `request-close` value