Change Details

//This is a placeholder – Neil to fill in details//

The [VisualEditorFeatureUse schema](https://meta.wikimedia.org/wiki/Schema:VisualEditorFeatureUse) is very permissive, consisting of the editing session ID and two unvalidated text fields. This makes it very easy to instrument for, since developer can simply log events when key UI code paths are called without having to know which exact events will result. However, this makes the data hard to analyze since the schema doesn't provide a definitive list of possible values and their meanings. We should keep the unvalidated nature of the schema, but make a data dictionary so at least we only need to figure out the meaning of each value once.