At the moment the h5p_get_content_types_task outputs the number of new content types. It would be good to see a little more information about the new content types. Since the core_h5p\core::fetch_latest_content_types() function returns the library name to the task, it should just be a case of iterating of the return result.

Example output:

6 new content types installed
 - H5P.Column 1.18
 - H5P.Flashcards 1.7
 - H5P.Dictation 1.3
 - H5P.BranchingScenario 1.8
 - H5P.InteractiveBook 1.9
 - H5P.Crossword 0.5