When you press “highlight values” in the “Viewer” section of the Workiva Report Tagging Tool, all tagged elements should be highlighted. Most of them will be highlighted in green, while a few may be marked with yellow. The yellow elements have been tagged using an extension to the ESEF taxonomy.
When you have an account in your annual report which is either more or less specific than what is covered in the taxonomy, an extension is made to cover the correct information related to that account. The extension is then anchored to any narrower and wider taxonomy elements which it relates to.
Furthermore, values that are highlighted with purple are tagged with more than one element. These values can be both numerical and non-numerical, but will most likely occur in the non-numerical tagging of the report.