I would like to know the concept of Querystring , what is it ? , what is it for ?. I am in a class on flask and was introduced to me about Querystring

Question

@app.route('/novo') #novo.html
def novo():
    if 'usuario_logado' not in session or session['usuario_logado'] == None:
            return redirect('/loguin?proxima=novo')
    return render_template('novo.html', titulo='Novo Jogo')

Return redirect('/loguin? next=new')