Because it seems like a pretty important change, but it seems to be getting lost in the noise about the 40 second clock coming in...
According to casebook play 7.2.5.C, a player lining up in "no man's land" does NOT result in an illegal formation, as long as there are still 5 correctly numbered linemen on the LOS. Anyone in "no man's land" is by definition not an end, nor is he a back, and he is INELIGIBLE to receive a forward pass.
*7.2.5 SITUATION C:
Team A comes to its line of scrimmage with tackles 70 and 71, guards 60 and 61, center 50 all on the line of scrimmage, a quarterback and three other backs in the backfield, and: (a) ends 80 and 89 on the line of scrimmage; (b) end 80 on the line of scrimmage and no other players on the field; (c) end 80 on the line of scrimmage and player 89 meeting neither the definition of a back nor a lineman; or (d) players 80 and 89 on the field meeting neither the definition of a back nor a lineman.
RULING: The formations and numbering in both (a) and (b) are legal because there are five players numbered 50-79 on the line of scrimmage, a minimum of five players on the line of scrimmage, and no more than four players meeting the definition of a back, including the quarterback. In both (c) and (d), the formations are legal because there are five players numbered 50-79 on the line of scrimmage, a minimum of five players on the line of scrimmage, and no more than four players meeting the definition of a back; however, the other players in the game are not eligible receivers in the event of a legal forward pass. (emphasis added)
I've seen several discussions on Facebook where people are saying this in an illegal formation foul. It's not! As long as you've got 5 Bubba's on the the LOS wearing a correct number, and you have 4 or less guys meeting the definition of a back, you
can't have an illegal formation foul.