For drupal 8, take a look into composer.json and checkout for 'extra' section. Add the file_mapping:
From time to time I stumble upon the following error message when creating a custom field type in drupal 8: "This value should be of the correct primitive type.".
With image styles and responsive breakpoints drupal generates automatically smaller images from the original uploaded ones.
I'm testing a setup with redis as cache for a drupal site - and I'm still thinking about one redis as caching solution for several drupal sites without critical content.
Strange but true: In drupal 8 you can place a rendered block entity into the views header - but only, if this block shows up anywhere, if it is placed in a region.