amperser/proselint is a repository of a linter that finds expression and style problems in English prose. A linter is a tool that inspects writing rather than code and points out problems. The '[Mirror]' tag on the repository description means it is a mirror (mirror) copied as-is from the proselint original. The most recent release on record is v0.16.0, and what this release changed is not stated in the given material.
proselint inspects English prose. Like a spell checker, it finds problems and returns suggestions for improving the text. You can check documents on the command line and print the suggestions, or export them in JSON format, and it can also be used as a library in Python programs. The checked items include clichés, redundant expressions, jargon, spelling, punctuation, and so on, and the configuration can be split by module or by file. The point this tool targets is sentence-level style. The primary language on record is JavaScript, the license is BSD-3-Clause, the star count is 4587, and the repository was created on January 14, 2015. The README explains that it can be used as a library in Python programs.
However, the evidence available for judgment is thin. The material contains no figures comparing it with other linters and no real adoption cases, and since it is a mirror, its sync status with the original is also unconfirmed. All that remains is the fact that it is a tool handling sentence style through the checked items the README lists. It is worth a look for confirming the basic shape of a prose inspection tool, but judging adoption on the basis of quality or performance is difficult with this material alone.