Re: master 8a88f3ed5ae: Add `outline-occur' command and `display-buffer-default-alist' variable

>> Thus we need a new variable like 'display-buffer-overriding-action',
>> but with both condition and action like in 'display-buffer-alist'.
>> So the complete precedence should look like this:
>>
>>   • The variable ‘display-buffer-overriding-action’.
>>   • The variable ‘display-buffer-overriding-alist’.   NEW!
>>   • The user option ‘display-buffer-alist’.
>>   • The variable ‘display-buffer-default-alist’.
>>   • The ACTION argument.
>
> I don't think it is clear to me what we are solving, if we are keeping
> without-local-variable-queries.  In that case we might as well just keep
> display-buffer-overriding-action?

Indeed, no need to replace 'display-buffer-overriding-action' here,
since it should prevent all possible windows from being displayed.
A new 'display-buffer-overriding-alist' might be required in other cases
where a known window category should be disabled selectively.