It also detects repetitions and some basic English language stuff if I recall correctly.
I've used it for my PhD manuscript, it's quite useful.
There’s also a set of style linting scripts by Matt Might [0] that I’ve found really helpful in my writing. There’s an emacs minor mode built around them too, writegood-mode [1]
0: https://matt.might.net/articles/shell-scripts-for-passive-vo...
In Matt Might's recommended reading section for that tool he points out Style: The Basics of Clarity and Grace by Joseph Williams, and reading that book and really learning a lot of things it shows will be much more helpful overall for your writing. Its use of contrasting examples is very effective. For instance, it shows how the passive voice can be a very powerful tool for controlling the flow of topics and ideas and actions in a sentence or paragraph. Through the passive voice you can improve the clarity and coherence of a piece of prose. As Matt Might says, it's about making it a conscious decision rather than to enforce all controlling rules.
I use a lot of hedging/weasel words in my first drafts so I find it helpful to have those highlighted for reconsideration