For end users do console errors and messages generate when they play the game ?

if you get console messages/warnings etc in unity and choose to leave them there… then

if you make a game and people download it and play will those messages keep generating somewhere there also? my point behind this is PERFORMANCE . if these message do generate they will slow end user game play down.

so do console messages only appear in unity or also in the game when downloaded

I think that you can disable the logs for Standalone builds by unchecking the Use Player Log option in the Player Settings (Resolution and Presentation > Standalone Player Options)

UsePlayerLog


Else, if you are using Unity 5.4+, take a look at the Player Settings. At the bottom of the Other Settings section, you will see Logging. Here, you can manage the logging level of errors, warnings, … Select None for all and it should be fine, I guess…

Don’t worry though, the log messages will never be shown to the player unless the Development Build and Script Debugging options are checked in your Build Settings

Logging


Last solution I’ve found, is by using a script to manage this :

#if DEVELOPMENT_BUILD
Debug.logger.logEnabled=true;
#else
Debug.logger.logEnabled=false;
#endif

Source : https://forum.unity3d.com/threads/is-it-possible-to-disable-all-debug-logs-in-builds.361553/#post-2781285