This has been posted by multiple sources and is explicitly public. For formatting reasons I have copy-pasted from Rorate, but Edward Pentin and Sandro Magister, among others, have also carried the document. The translation is official, from the authors.
This is an important letter. We debated the proper intent behind Amoris Laetitia, and the most correct interpretations thereof several times in the past. What Cardinals Brandmuller, Burke, Caffarra, and Meisner have asked of Pope Francis and