this is the document the post was referring to
https://www.dni.gov/files/documents/icotr/RawSIGINTGuidelines-as-approved-redacted.pdf
apparently it was set to be declassified in 2041 but they actually released a redacted version in 2019 already
in addition it seems to be important because if you check the dates and signatures at the bottom of the document, Clapper and Lynch signed this document after Trump won in 2016 but before he became president. the document contains provisions on what data intelligence services can get from NSA.
if I understand correctly, Obama quickly needed some sort of backdoor access after Hillary lost (which this plan was only to be disclosed in 2041, years after the fact) but Trump published this plan by declassifying the document later (I don't know when the document was released / declassified)