For sending email from the onArticleDelete hook, I would reccomend using the content language for messages ending up in the email (e.g. wfMessage->( 'foo' )->inContentLanguage()->text() instead of wfMessage->( 'foo' )->text() ). Otherwise this will use whatever language the admin who deletes the page has set in their preferences (which the person being emailed might not understand). As it stands there is only an english translation for this extension, so it would be a non-issue in practise, but if the extension added more translations, this could be an issue.
Extension talk:EmailDeletedPages
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