Hi Elastic folks,
I have a proposal to improve your documentation for the Elastic Common Schema. I would suggest to reference the filebeat modules for common log sources in the ECS documentation. E.g. under Additional Information.
I just noticed those after I put some effort in doing my own ECS normalization of PANOS logs via logstash. Would have helped me a great time to borrow from the module documentation and the ingest pipeline to not fully come up with my own mapping. 
Anyhow could be a great pointer in the ECS documentation. Kind of like "And here is how we at Elastic would normalize these common log sources". And to really make our lifes a lot easier you could also provide a logstash config doing the same adaption like the corresponding input.yml and pipeline.yml. After all some of us use logstash for the whole log parsing instead of ingest pipelines. 
Best regards,
Sebastian
