In some environments, and whether anonymization is enabled or not, the bundle generation might take a long time but collecting thread dumps is not always pointing to the culprit, especially when Support Core is writing / anonymizing a specific content.

I can be hard to identify which component / content is causing a slowness in the bundle generation.

https://issues.jenkins.io/browse/JENKINS-61815 should eventually help solve that problem but in the meantime, I cheap improvement can simply be to add some logging of what content and component t is being processes.