Feature summary:
Creating a __NOTRANSLATE__ magic word which will disable Translate parsing, so that the page cannot be marked for translation and is not displayed in “Pages proposed for translation” at Special:PageTranslation.

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
Some pages may contain translate tags whereas they are not expected to be marked for translation (yet), e.g.: drafts, talk pages, templates for copy-paste, sandboxes, etc.

Benefits:
This would avoid a page is marked for translation whereas it should not. So translators will not do useless work, and translation admins to-do list is clearer in Special:PageTranslation.