Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
It works now.
A fix has been deployed, now 7.4 also shows the log information as it should.
It is indeed not showing the debug information in 7.4, change the version to 7.0 and it'll show. It's not a kata specific problem, and I already reported it as an issue here
Google "php print array".