infodump

/IH1 N F AH0 D AH1 M P/
noun
  1. 1

    A large volume of data supplied at the same time.

  2. 2

    (authorship) A long section in a work of fiction that reveals often tedious expository information through the voice of the narrator.

Source: https://en.wiktionary.org/wiki/info-dump, https://en.wiktionary.org/wiki/infodump