I think I wrote it wrong. Activity, or rather a query, appears after creating a library of API queries to the Orchestrator in UiPath via a link from Swagger. Then these activities (queries) appear on the list.
Here a link to a topic where it is explained step by step.
Anil_G
mkankatala
Oozair_Khan
Vinit_Mhatre
topology271828
adi.mehare
singh_sumit
Eric_Alvarado
esongi_park
Kismet_Tosun