This Plugin shows a warning, when the visitors browser was made by a prism-contributing company.
So far there is a english and a german translation. You can contribute more languages, if you want. Just open a pull request on GitHub.
Please note that this is still work in progress. (As you can see by the version number which has not reached 1.0 yet.) If you want to contribute, write you code and submit it at GitHub.
If you don’t know how to code but still want to contribute, please take a few minutes to write a friendly recommendation or tell your friends about this.
I use the 0.x numbers on WordPress SVN (no buggy code there) and then publish the newer (buggy) code on GitHub with a version like 0.x.1.