Hello,

On 2023-01-05 09:26, Ihor Radchenko <yantar92@posteo.net> writes:

> If you look inside `org-beamer--format-block', it uses
> `org-beamer-environments-default' and `org-beamer-environments-extra' to
> format the blocks. See docstring for the latter for details.
>
> The code responsible for LaTeX block generation is
>
>      (when (nth 2 env-format) ; when we non-column block
>       (concat
>        (org-fill-template ...) ; opening \begin lines
>        contents ; block body
>        ... ; block closing \end lines
>        )
>
> org-fill-template is using the template from the
> `org-beamer-environments-*' replacing %-chars as described in the
> docstring.
>
> In order to handle CUSTOM_ID property, you can
> (1) Introduce a new %-substitude to be handled in org-fill-template
>     call. It will insert block ID. (for example, using
>     `org-beamer--get-label')
> (2) modify `org-beamer-environments-default' to insert label
>     appropriately.
>
> Patches welcome!

Thank you for the detailed instructions. Here is my attempt at this.
I’ve tested it and it works.