In the Movie “First Contact,” the Borg sent a smaller ship (a sphere from one of the cubes) back in time to assimilate Earth before us clever humans devolved warp technology. This time period is about 100 years before the Enterprise show takes place. Anyway, Captain Picard follows the sphere back in time, saves the day, and ends up destroying this sphere.

Fast forward 100 years. The wreckage of this sphere is found in the artic along with two Borg bodies.

The ship the Borg was on was a modified Earth ship. I am guessing they used the material from the crash site to modify it.

Notice the Borg did not say , “We are the Borg. You will be assimilated. Resistance is futile.” They just say, “You will be assimilated. Resistance is futile.”

Also notice Captain Archer mentioned the Borg will be a problem in 200 years- Picard's time period.

I kept expecting Captain Archer’s temporal friend to show up and set history right, or maybe Q, but they didn’t. I would say that the writers should, in relation to The Next Generation, DS9, and Voyager series, should just say “the time line has changed, because the Borg and Picard traveled back in time and Changed History.” I suspect they will ignore it, or write some wild explanation for it.