The words in question are: "Ownership is Rust’s most unique feature,..."

Unique should be a binary value. Either something is unique or it is not. From Merriam Webster:

1 : being the only one : sole

It is acceptable to use it in a non-binary form as specified in the third definition listed on Merriam Webster, but doing so can disrupt the fluid reading by people that prefer a more strict definition of "unique".

I recommend changing the phrase to "Ownership is Rust's most distinctive feature". This expresses the same concept as the original without possibly angering people who prefer to read "unique" as a binary value.