The client is fully capable of receiving rich disconnect reasons, but the disconnect GUI does not support clickEvent.
If the disconnect GUI supported clickEvent, servers could serve links in disconnect reasons, such as using open_url to a whitelist application form.
I acknowledge the security concerns with this. It would probably be best to only support open_url, respecting the client's chat settings.
Thank you for your report!
However, this issue has been closed as Invalid.
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