How does middleware work in chi routing in Go and what does http.Handler argument refers to in middleware?

--  routes.go --package mainimport ("hotelsystem/pkg/config""hotelsystem/pkg/handlers""net/http""github.com/go-chi/chi/v5""github.com/go-chi/chi/v5/middleware")func routes(app *config.AppConfig) http.Handler {    mux := chi.NewRouter()    mux.Use(middleware.Recoverer)    mux.Use(WriteToConsole)    mux.Get("/", handlers.Repo.Home)    mux.Get("/about", handlers.Repo.About)    return mux}-- middleware.go --package mainimport ("fmt""net/http")func WriteToConsole(next http.Handler) http.Handler {    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {        fmt.Println("Hit the page")        next.ServeHTTP(w, r)    })}-- main.go --package mainimport ("hotelsystem/pkg/config""hotelsystem/pkg/handlers""hotelsystem/pkg/render""log""net/http")const portNumber = ":3000"func main() {    var app config.AppConfig    tc, err := render.CreateTemplateCache()    if err != nil {        log.Fatal("Can't create templatecache", err)    }    app.TemplateCache = tc    app.UseCache = false    repo := handlers.NewRepo(&app)    handlers.NewHandlers(repo)    render.NewTemplate(&app)    // http.HandleFunc("/", handlers.Repo.Home)    // http.HandleFunc("/about", handlers.Repo.About)    // http.ListenAndServe(portNumber, nil)    srv := &http.Server{        Addr:    portNumber,        Handler: routes(&app),    }    err = srv.ListenAndServe()    if err != nil {        log.Fatal(err)    }}

I am having a hard time understanding the middleware.

I am using chi for routing.

What I didn't understand is what does that (next http.Handler) argument in the WriteToConsole refers to?

Does it refer to our mux router?

Also when I comment down the line next.ServeHTTP of function writetoconsole the html is not rendered or anything? can someone explain me what does that next http.Handler refers to and what next.serveHTTP does?