I've reviewed the code of this extension (Digest 3b2de07401057969f35e00ddf5344c0d61547b8999495ec1f1a5696f17f42e32) which has not been changed in two years; I did not find any malicious code.

When installed from the Chrome Web Store, the extension properly displays in chrome://extensions/. 

Nothing interesting happens when the extension is uninstalled (there's no uninstall handler); the extension is just immediately removed.

If you can supply screenshots showing the extension in your toolbar but not appearing in chrome://extensions, and/or of the "redirecting to third party" page you refer to above, please do update this issue. It's possible that you have native code malware in your operating system that's doing something sneaky, but it's not coming from the extension served by the Chrome Web Store.

This bug has been closed for more than 14 weeks. Removing security view restrictions.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot