Search engines unique to non-default distributions and partner build are still defined in the OpenSearch XML format, whereas the built-in engines have been converted to WebExtensions quite a while ago.

Goal of this bug is to get to an actionable state and find a way to convert these engines in a way that's future-proof.

Mike (Kaply), do you have thoughts and knowledge to share that'd help us? If you'd rather do this in a call, we're up for it!

We're going to discuss this in Berlin, and we'll post something here.

Here is a writeup I did with some thoughts on how to handle this.

https://docs.google.com/document/d/1HQTa_JLstdDSYtRYnelRfu7xV7_8Ay-xOIKp5r2P9_s

In discussion at Berlin we decided that we would move the distribution engines across to the new configuration, this would then remove the need for distributing separate files and handling loading extensions from different places.