This is almost certainly a bet by Ted Weschler or Todd Combs - Buffett's chief investing lieutenants.
Buffett has maintained his aversion to tech as he doesn't "understand"[1] it, and I see nothing to indicate he's changed his mind at this stage in the game.
Also - a $1bn investment is relatively small change for Buffett, but fits squarely within the size range of Ted and Todd's reported $8-10b (each) investment warchest.
[1]: Not "understanding" doesn't mean he doesn't or couldn't understand the technology aspects; rather, it means he doesn't have the ability to see which of the participants will survive and thrive in 10 years time to justify an investment today. IBM is a notable exception.