Summary in module pages: possible?

(First Time Post) Hello and thank you for this fantastic CMS.
I've got one question: I am trying to output page.summary on a modular page template.
I've read the forum and found that it is related to https://github.com/getgrav/grav/issues/991 (on modular pages twig is processed through Twig first).

Unfortunately I don't understand how to output (if even possible) the summary in a modular template; I've just used the default installation with antimatter, copied the modular template "text.html.twig", renamed it to "shortened.html.twig" and changed {{content}} to {{page.summary}} - and it's showing the whole page text.

Sorry, I am new to grav and to Twig, maybe I am missing something.

Thanks in advance,
steppo

Does the page have a summary? It must be separated from the rest of the text, see https://learn.getgrav.org/content/headers#summary & https://learn.getgrav.org/content/content-pages#summary-size-and-separator

Yes it has. The delimiter === doesn't show up on the output but the output is not truncated - {{page.summary}} outputs always the whole page (without the delimiter).