This is the XL version of https://civitai.com/models/159990/negativedynamics
The XL version behaves a little differently and is perhaps more effective, The SD 1.5 version does not work as intended in XL.
This is a negative embedding, you need "NDXL" in the negative prompt. Without the trigger word(filename) in the prompt embeddings will do nothing.
Negative Dynamics was an attempt to normalize disproportionate limbs, which seems to work in most cases, while being as neutral as possible on image output. There were some unexpected side effects though such as changes to face structure, improvements to image quality and some additional context. I find the result useful in most circumstances no matter the subject.
Effects are dynamic and have greater impact with simpler prompts. Exactly what and how much it contributes will depend on the model used and how responsive it is. NDXL generally won't override any prompt, embedding or lora etc. For best effect place it at the very start of the negative prompt, you can reduce the strength somewhat with parenthesis and colons, i.e. (NDXL:0.5).
Extensive negative prompts generally only have a negative impact upon image output and reduce accuracy. Many words simply don't work as intended and will have different effects dependent on model training. Do some tests with and without each keyword and only add what is necessary. Also watch out for typos, they're the worst.