This is a papal shoe belonging to and worn by Blessed Pius IX, and, because of his beatification, it is also a 2nd class relic. The shoe contains a document of authenticity, stating it belonged to and was worn by the Pope. It is obviously worn on the toe, testifying to the fact that he did, indeed, wear this pair of shoes.
Papal shoes vary depending upon the location of the pope. He wears red leather outdoor shoes. They should not be confused with the indoor papal slippers. (Papal Artifacts has a slipper belonging to and worn by Pope Pius XII.)
Before 1969, the pope wore episcopal sandals during the Mass and the color of the sandals matched the various liturgical colors of the vestments. Outdoor shoes were made of plain red Morocco leather and also had a wide cross in gold braid. Various modern popes added and eliminated decorations on their shoes according to their own personal tastes.
Popes also have their own personal cobblers in Rome.
The red shoes are one of the few remnants, along with the camauro, papal mozzetta and tabarro that are of the former red color of papal garments.
Pope Francis has dispensed with red shoes!