I am looking to implement Edge for a customer early in 2020, and things so far look fantastic. One missing piece is the ability to mimic their current Search Engine policy, which is basically google by default, but you can select Bing. This is easy enough to do in Legacy Edge, but the policy controlling it in new Edge (called ManagedSearchEngines - https://docs.microsoft.com/en-us/deployedge/microsoft-edge-policies#managedsearchengines) could not be more complicated.
The JSON example is of little use. It would be great if we could start by exporting out the current configuration as it has all of the correct search engines, and we could just modify the "is_default" field to the correct entry.
I've tried looking for this configuration in files in the User Data folder, but it doesn't seem to exist in an unencrypted form anywhere.
The "ManagedSearchEngines" GPO is of little use anyway. While it will actually add the configured search engines to your Edge, the "is_default" attribute is completely ignored (under certain, unknown circumstances).
I was able to get it to work some of the time ... but at least after resetting Edge back to defaults it switched back to Bing as the default search engine, not what I have configured in the GPO.