[JENKINS-22764] Record update center information

Often people say they are not seeing an expected plugin update. Would be useful for a support bundle to record:

• list of configured update sites


• core version string being sent to them


• registered site certificates


• last update time


• pending plugin updates (could be moved from about.md, or just shown in a different form: list of plugins, with current and newest versions)


• status of Downloader instances (tool definitions, usually)


• whether a proxy is configured

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Originally reported by jglick, imported from: Record update center information

• status: Open
  
• priority: Major
  
• component(s): support-core-plugin
  
• resolution: Unresolved
  
• votes: 0
  
• watchers: 2
  
• imported: 20251212-090250
  

Raw content of original issue

Often people say they are not seeing an expected plugin update. Would be useful for a support bundle to record:




	
list of configured update sites

	
core version string being sent to them

	
registered site certificates

	
last update time

	
pending plugin updates (could be moved from about.md, or just shown in a different form: list of plugins, with current and newest versions)

	
status of Downloader instances (tool definitions, usually)

	
whether a proxy is configured

Start by reviewing how the support bundle collects existing update information, including the content currently described in about.md and the status of Downloader instances. Define the collected fields for update sites, certificates, versions, timestamps, pending plugin updates, Downloader instances, and proxy configuration. Done means the support bundle records this information in a usable form.

Written by the indexing model from the issue text.