Add Debug Helper plugin

plugins/optimization-detective/docs/extensions.md

@@ -43,11 +43,12 @@ Stable plugins for use in production from the WordPress.org Plugin Directory:
 Experimental plugins being explored exploration, from repositories on GitHub:
 
 * [Optimization Detective Content Visibility](https://github.com/westonruter/od-content-visibility): Applies content-visibility to posts in The Loop to improve rendering performance.
-* [Optimization Detective Intrinsic Dimensions](https://github.com/westonruter/od-intrinsic-dimensions): Supplies width and height attributes to IMG and VIDEO tags that lack them according to their intrinsic dimensions. This reduces Cumulative Layout Shift (CLS). 
+* [Optimization Detective Intrinsic Dimensions](https://github.com/westonruter/od-intrinsic-dimensions): Supplies width and height attributes to IMG and VIDEO tags that lack them according to their intrinsic dimensions. This reduces Cumulative Layout Shift (CLS).
 
 For development and debugging, also on GitHub:
 
 * [Optimization Detective Admin UI](https://github.com/westonruter/od-admin-ui): Provides an admin UI to inspect URL Metrics from the Optimization Detective plugin.
+* [Optimization Detective Debug Helper](https://github.com/swissspidy/od-debug-helper/): Makes data from Optimization Detective visible on the front end through the admin bar.
 * [Optimization Detective Store Query Vars](https://github.com/westonruter/od-store-query-vars): Stores the Query Vars with a URL Metric in the Optimization Detective plugin. This is useful for debugging URL Metrics, in particular what the slug was computed from.
 * [Optimization Detective Store User Agent](https://github.com/westonruter/od-store-user-agent): Stores the User Agent with a URL Metric in the Optimization Detective plugin. This is useful for debugging URL Metrics, in particular to understand what device has a given viewport dimensions.
 * [Optimization Detective Dev Mode](https://github.com/westonruter/od-dev-mode): Adds filters to facilitate development of the Optimization Detective plugin.