h5p.org has to be removed as default value for the allowedsources in
the "Display H5P" filter because H5P is going to close it down completely
so that only the author can see the test content.
We are renaming existing h5p_filter in 3.8dev to h5p_displayh5p to avoid collisions with filter_h5p plugin
in Moodle plugin directory.
Everybody having a 3.8dev installation with filter_h5p plugin should drop the old filter or re-install from scratch.