Hi Eli,
> "Background" is a problematic word for this, since that's not what you
> mean: you mean not to select the window displaying the URL.
>
> And I don't think we need a separate command for that: how about doing
> this in eww-open-in-new-buffer instead, if the user invokes it with a
> prefix argument C-u?
>
> And finally, what happens if the following condition, tested by
> eww-open-in-new-buffer, is fulfilled:
>
>       (when (or (eq eww-browse-url-new-window-is-tab t)
>                 (and (eq eww-browse-url-new-window-is-tab 'tab-bar)
>                      tab-bar-mode))
>
> In this case, AFAIU the URL is opened in a new tab.

Thank you for the comment, and agree with you, so I rewrote the
function `eww-open-in-new-buffer' with "C-u" support (also with an
optional argument "url"), then there is no "background" description.

I also tested the new patch with tab-bar-mode on and off, it works for
both scenarios.

Please help review again. Thanks.

Best regards
Lin