The Slack bot that Jira's integration creates is supposed to be able to recognize issue numbers and render previews in Slack channels as advertised here:
It's not working, which we have reported. The Jira support team has created a support case for this, linked below. Unfortunately it's a low priority for them. If you use the Slack integration and value this feature as we do, I encourage you to view the link below and vote for a resolution.
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