This doesn't have any effect on headers

[Mehdi-Hp]

Marker doesn't add any mark to headers. even in the live demo on the website.

[mydearxym]

and link tool also not work on Header, i think mark and link should not appear in inline-toolbar

[SalahAdDin]

and link tool also does not work on the Header, I think mark and link should not appear in inline-toolbar

You can hide them on the Editor config.

If you think it is something to be improved, you could open a pull request.