Workflow

1. At the start of a UXP-based browser session, a js or a script in appropriate language will select a random online searx instance from searx.space and assign it somehow to the xml file.
2. xml file will be installed as a search plugin at the start of the browser session for searching throughout the session.

Checkout OpenSearchDescription https://github.com/dewitt/opensearch/blob/master/opensearch-1-1-draft-6.md#opensearch-description-elements