How to find parent theme url or dir in twig template

I'm trying to access parent theme url or dir in my theme child, all themes variable return the theme child, of course normal behavior, but need to access theme parent url or dir in my theme child.

Thanks

Not quite clear what parent theme and child theme, but maybe so:

{{ url('theme://...') }} or
{{ theme.url }}
---

@Stanislav thanks, but

{{ url('theme://...') }} or
{{ theme.url }}

return the active theme and in my case the active theme is the theme child and i'm looking for the parent theme (theme-inheritance) see here