Affinity Publisher

An application was installed on Petronella Osgood's computer by 10 May 2020. Its logo was an orange square with its upper-left corner coloured red, and which had 4 lines diagonally over the square. (WC: The Zygon Isolation)

Behind the scenes
While the application was not named in WC: The Zygon Isolation, the application was named "Affinity Publisher" in the real world, and was a desktop publishing application created in a group of products along with Affinity Photo and Affinity Designer.