Does nothing. Unsurprising since it looks like abandoned-ware with the last update being over three years ago.

This extension is outdated and urgently needs an update. I installed it and nothing worked. If you are no longer interested in further developing your extension, please delete your extension from the Firefox homepage. It does not have to be that others also install your garbage extension.

Perhaps because of how old this extension is, it does not do anything to hide the sidebar on Amazon. Uninstalling because it doesn't do what it claims to, at least as of Jan 2024.