Feature summary:
Given a translatable EditIntroTemplate English page.
With the following URL, I would like the edit intro to be in my user interface language or in an appropriate fallback language chen there is no translation for my language:
index.php?action=edit&editintro=Special:MyLanguage/EditIntroTemplate&title=My_new_page
The same feature has already been implemented for preload param in T299544.
Use case(s):
Provide guidelines in user language about how to edit the page.
Grants already use a workaround
Benefits:
The workaround ({{#ifexist:EditIntroTemplate/{{PAGELANGUAGE}} |EditIntroTemplate/{{PAGELANGUAGE}} | EditIntroTemplate }}) does not allow to benefit from language fallback chain.