In theory, the functionality is present in terms of processing thresholds, as you can see here:

https://github.com/OpenNMS/opennms/pull/2713/files

Unfortunately, validations on thresholds.xml prevents the usage of this feature.

Here are the two major problems:

1) You cannot use the meta-data format on the value when defining thresholds through the WebUI, as it silently ignores the content as it expects a number:

https://github.com/OpenNMS/opennms/blob/opennms-26.0.0-1/opennms-webapp/src/main/java/org/opennms/web/controller/admin/thresholds/ThresholdController.java#L604

Based on the above code, you'll see an error like the following on web.log:

2) You cannot manually set the value with meta-data format directly on threhsolds.xml because the XSD validation fails.

Another side effect of this is because `config-tester` fails if there is meta-data content on `threhsolds.xml` OpenNMS won't start.

In conclusion, you cannot use the meta-data feature with thresholds until the code is changed to properly handle the case when the value is not a Java Double.