While the name suggests that it's another general-purpose JPEG library, it's actually closer to the jpegoptim optimization tool.
>From the upstream README:
"'mozjpeg' is not intended to be a general JPEG library replacement. It makes tradeoffs that are intended to benefit Web use cases and focuses solely on improving encoding. It is best used as part of a Web encoding workflow. For a general JPEG library (e.g. your system libjpeg), especially if you care about decoding, we recommend libjpeg-turbo."
mozjpeg ships two binaries that allow one to recompress JPEG files so that they become smaller:
I would personally like to use it in my web development projects, so Pierre, if you'd like to reupload your package to mentors, I will take a look at it.