Aniyomi is a app for watching anime and reading manga (it is a fork of Tachiyomi which does the same but only for manga). It uses extensions for the sources it pulls anime/manga from (like aniwave for anime or mangadex for manga). Aniyomi needs the extensions to use external sources, else it can be only used to watch/read anime/manga you already have on your phone

My guess would be the suck and spez