The bug

If commands returns multiple lines of feedback the following lines have an indentation. This is not the case for the commands /whitelist list and /banlist.

How to reproduce

1. Add yourself to the whitelist

   /whitelist add <player>
   

2. List all whitelisted players

   /whitelist list
   

   → Your username is not indented

The reason

The following is based on decompiled version of Minecraft 1.9 using MCP 9.24 beta. All method and class names are the names used in the decompiled version.

The according methods send two chat messages. The first one is the headline "There are X (out of X seen) whitelisted players:" and the second one contains all the whitelisted players.