sometime during bigger translation tasks I18N labels might get lost and the ui does not reflect missing labels right now.
for debugging purposes it would be good to enable some kind of logging or default ERROR.

this could be achieved by making the LabelLoader class configurable in Labels.class so that the getLabel(...) methods can be overridden to return
a default indicating a missing label if the value would be null (or write a log for failed missing label properties)

this would help for this case:
missing label bla: <label value="${c:l('bla')}"></label>
e.g. output: -> missing label bla: [ERROR missing label 'bla']

in case of getSegmentedLabels... it would help to provide some mechanism to achieve the same with the nested filtered maps
for this case:
missing label bla: <label value="${labels.bla}"></label>
e.g. output: -> missing label bla: [missing 'bla']