Google's ML framework — less popular than PyTorch for new research but still the basis of much production inference (especially mobile via TFLite).
From Wikipedia
TensorFlow is a software library for machine learning and artificial intelligence. It can be used across a range of tasks, but is used mainly for training and inference of neural networks. It is one of the most popular deep learning frameworks, alongside others such as PyTorch. It is free and open-source software released under the Apache License 2.0.