>>> Since LLMs and in general deep models are poorly understood ...

>> This is demonstrably wrong.

> That doesn't mean we _understand_ them ...

The previous reply discussed the LLM portion of the original sentence fragment, whereas this post addresses the "deep model" branch.

This article[0] gives a high-level description of "deep learning" as it relates to LLM's. Additionally, this post[1] provides a succinct definition of "DNN's" thusly:

  What Is a Deep Neural Network?
  
  A deep neural network is a type of artificial neural 
  network (ANN) with multiple layers between its input and 
  output layers. Each layer consists of multiple nodes that 
  perform computations on input data. Another common name for 
  a DNN is a deep net.
  
  The “deep” in deep nets refers to the presence of multiple 
  hidden layers that enable the network to learn complex 
  representations from input data. These hidden layers enable 
  DNNs to solve complex ML tasks more “shallow” artificial 
  networks cannot handle.

Hopefully the above helps demystify this topic.

0 - https://mljourney.com/is-llm-machine-learning-or-deep-learni...

1 - https://medium.com/@zemim/deep-neural-network-dnn-explained-...

2 - https://learn.microsoft.com/en-us/dotnet/machine-learning/de...

3 - https://www.sciencenewstoday.org/deep-learning-demystified-t...

4 - https://www.ibm.com/think/topics/deep-learning