I'm pretty sure that the expansion doesn't work for 'defaults:',
but I can't now recall whether there was a reason for that.
Maybe submit a bug report?

BPJ <melroch-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> writes:

> I forgot to mention the vital points that `${HOME}...` works with `css: []`
> in the same file and that everything works if I use an absolute path in the
> `defaults: []` entry.
>
> Den lör 21 maj 2022 20:45BPJ <melroch-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> skrev:
>
>> In a defaults file in the current directory I have the lines:
>>
>> ``````yaml
>> defaults:
>>   - ${HOME}/style/ling-html2pdf.yaml
>> ``````
>>
>> I'm sure that file exists but pandoc complains and says it doesn't. Might
>> Pandoc's idea of what `${HOME}` expands to differ from the shell's idea of
>> what `$HOME` expands to?
>>
>>
>>
>
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