The Donlon AIXM data set describes a fictitious airport and the surrounding airspace, located somewhere in the middle of the Atlantic. It is derived from the similar content of the ICAO AIP Template (Doc 8126), complemented with additional data items (such as Runway/Taxiway Elements), to make it more realistic as AIXM data set. See Donlon data on the AIXM Wiki.
When we started to implement the WFS Temporality Extension, which is based on the Donlon Data Set, we found some issues regarding the timeslice encoding. So we moved the Donlon data repository to GitHub on behalf of EUROCONTROL and the AIXM community for further maintenance. See Donlon data repository on GitHub.