People have argued both cases. The tl;dr is that she said "I will resign if XYZ" and Google was like "we accept your resignation effective immediately." Whether or not that counts as firing is a matter of opinion.

She made demands and gave a resignation date if those demands were not met. Google said that they could not meet those demands and accepted her resignation but because of her conduct (emailing hundreds of Googlers), the resignation date was made immediate.

Timnit: "if you don't give me x, then i am going to do y in a week."

Google: "we aren't going to give you x, so you can have y. in fact, you can have y starting right now."

i'd say she tendered a conditional resignation and they called her bluff and accepted it.

It's fuzzy, and people are disagreeing about which aspect to emphasize.

The headline on the platformer.news article was updated to reflect the fact that she was fired.