f) Requests could and should have been filed during first-instance proceedings 

In T 1421/20 the board considered that the auxiliary requests at issue (0b', 0b'-1 and 0c'), which had been filed after the board had issued the summons to oral proceedings and which contained features which had never been included in any of the claims filed and discussed before the examination division, could and should have been filed during first-instance proceedings. Moreover, the board considered that it could not deal with requests comprising such features without undue burden, since it was not even certain that appropriate prior art was readily available in the file. Exercising its discretion under Art. 13 RPBA 2020, the board decided not to admit the requests into the proceedings.