Why is Amazon excluded from my search engine choices

We don't have that information. Of course you can add it back by yourself.

To be precise, it has been removed globally.

Amazon was removed as a built-in search engine according to the [https://www.firefox.com/en-US/firefox/157.0/releasenotes/#:~:text=Amazon Firefox 157 release notes]. YOu can add Amazon Search as a custom search engine by following the instructions in the '''Add a custom search engine from a supported website''' section of the [[Add custom search engines in Firefox]] article: # Go to https://www.amazon.com/ # Right-click the "Search Amazon" bar and select "Add Search Engine" from the drop-down menu