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