Looking for documentation for "if" parameter on ingest pipeline processor

Versions (relevant - OpenSearch/Dashboard/Server OS/Browser):
current

Describe the issue:

im looking for documentation of the if parameter which is shown on all the ingest processors eg Grok - OpenSearch Documentation

The documentation states “A condition for running the processor.” but its not clear what condition this refers to. and there are no links to further information

In Elastic there is a section on the documentation - see Elasticsearch ingest pipelines | Elastic documentation

Something like this needs to be added to the opensearch documentation.

Specifically i would like to know whether stored scripts can be used for the if parameter for opensearch as they can in elastic.

Relevant Logs or Screenshots:
see links above

There’s a new created issue in the document-website repo in Github, the documentation may be added soon.