Wardens can crawl out and dig in the some illegal blocks that are not normally obtained to survival mode players.
This can cause a lot of trouble for game map creators.
May cause wardens to spawn in places not intended by the map creators.
Affected illegal blocks:
Bedrock
Barrier
Command block
Chain command block
Repeating command block
End portal frame
Spawner
Structure block
Might be intended due to the fix of MC-249384.