This panel displays the result of validation on the currently opened setup.
It is one of the panels at the right of the mannequin editor. To access it simply press the "Error Report" tab at the bottom.
Every time you open a preview setup validation is done on that setup. If any errors are found, the error report will pop up to the front automatically.
This area shows the list of errors/warnings the validation found.
Double click a line to select that fragment in the fragment browser/editor.
Select one or more lines to operate on those fragments using the menu or right click menu.