The 1896 shirt that Udinese wore (or as it was called back then, Società Polisportiva Ginnastica e Scherma), featured a ...white star in the middle of the shirt, with the symbol of the city of Udine over the heart.
The team won the very first italian championship, although it has never been recognised by the league, as the rules were of the game were slightly different and the FIGC was only founded two years later in 1898.
Here you can see club legend Antonio Di Natale and some youth team players wearing the replica shirts. The third black and white picture is a team picture taken in 1896, of that squad that won the league that was never to be recognised.
It is now a tradition that every yearly Milestone the club reaches, they make a celebrative black shirt (as seen in 2016 and 2021 for the respective 120 and 125 years of the club), in order to honour the tradition and passion that has been present in these lands ever since.