Presently essentials.yaml includes a number of plugins which could be considered "top-level" dependencies for Jenkins Essentials such as workflow-aggregator.

Some tooling needs to be in place to generate the appropriate essentials.yaml with all the dependencies within it.

jglick suggested taking a look at some maven tooling he has used before:

• https://github.com/jenkinsci/workflow-aggregator-plugin/blob/2fd92539829c9b066ca4b4b65b50d6c4a403f9e1/demo/pom.xml#L5-L38
• https://github.com/jenkinsci/workflow-aggregator-plugin/blob/2fd92539829c9b066ca4b4b65b50d6c4a403f9e1/demo/Makefile#L5-L12

Meanwhile oleg_nenashev points out this issue for the custom-war-packager