From ESPN (h/t The Night Owl):
The CBA was set to expire at the end of Thursday, but a 24-hour reprieve was granted. Now, the sides have until midnight of next Friday going into March 12 to work on a new deal.
...
The extension of the CBA also includes a "tolling agreement"; in this scenario, the league's 32 teams still will be prohibited from executing player transactions. It is the same agreement reached Thursday. During this period, teams can talk about players but signings or renegotiations of current contracts cannot occur.
The union technically did not sign off on the arrangement but it is considered a minor detail compared to the major issues that must be resolved on a new CBA and, therefore, not a battle the NFLPA is fighting at this time.
First a 24-hour extension, and now a one week extension. Could it actually be that they're moving closer to an agreement? Or are they just posturing for the public?