It seems that the description of the download_dashboard document is incorrect.

[nsano-rururu]

I found a statement in a previous issue on yelp / elastalert that the download_dashboard documentation was incorrect. Since download_dashboard is not used, we have not confirmed the operation.
Also, since it is described as kibana3, it is unknown whether it will work with kibana3 or later.

filter download_dashboard AttributeError: 'dict' object has no attribute 'insert'
YelpArchive/elastalert#1481

[nsano-rururu]

There is information that it does not work with Kibana 5

Load filters from a Kibana 5 dashboard
YelpArchive/elastalert#949

[nsano-rururu]

Looking at the source code, it seems that Kibana 5 and 6 are compatible, and kibana 7 is not.
https://github.com/jertel/elastalert2/blob/master/elastalert/rule_from_kibana.py

[nsano-rururu]

I also checked use_kibana4_dashboard.
Since it worked with kibana 7.14.0, kibana 7 is also supported.

example

alert_text: "{}"
alert_text_args:
  - "kibana_link"
use_kibana4_dashboard: "http://127.0.0.1:5601/app/kibana#/dashboard/07bdfc10-f7fd-11eb-84fa-a33bdb7fffd8"

07bdfc10-f7fd-11eb-84fa-a33bdb7fffd8 is Dashboard ID.

[nsano-rururu]

download_dashboard doesn't work on kibana 7 as TODO commented.