How to Create Tags For Elements From the IFRS Taxonomy

If an issuer determines that the IFRS Taxonomy includes an element that corresponds to a disclosure of the issuer in its IFRS financial statements and that this element is not yet included in the ESEF taxonomy, then they may define an extension taxonomy element with the matching name, label, and XBRL characteristics. See example below.

For instructions on how to create an extension, see this page.