What does plan B of the Champions League mean?

According to UEFA's regulations, a maximum of 25 players can be submitted to the Champions League A list, including 4 "players trained by our own team" (who worked in our club for more than 3 years before the age of 265,438+0) and 8 "players trained by our own football association" (who registered in our football association for more than 3 years before the age of 265,438+0). Those who meet the conditions of "self-training of our team" automatically meet the conditions of "self-training of our Football Association"; There is no limit to the number of players in the Champions League B list, but they must be under 2 1 and have played for the club for 2 years.