Squashed 'core/' changes from 7884f98..fdeed66

fdeed66 Added a stronger warning message to #154, ready to be merged

git-subtree-dir: core
git-subtree-split: fdeed6660683bd3d845b72f9a88017e9d17b623a
Merge commit 'df22a2e6a7730d6e2e2a1ab4eb199752d07c0c4b' into bugfix/plugin-conflicts