Each DBDOC build generates: an .M14 file; build reports (with .ERR /.TXT file extensions) and other project files.
More information about .M14 files is available within BuildPlus help and Hyperview help.
DBDOC provides lists of .ERR files, including
Most of the issues identified in your system are not truly errors you need to be concerned about.
To begin understanding your build reports (.ERR) and other files generated by DBDOC and how they can be used to improve your system: