"View the Atlassian Marketplace" link on Administrator's Tasks is broken

Symptoms

When opening up the Confluence Administration Console, the initial screen is a list of administrator's tasks. One of the tasks here is "View the Atlassian Marketplace" and contains a link. The link on this is broken, pointing to the URL:

<base_url>/admin/{0}

Steps to Reproduce

1. (cog-wheel icon) > Confluence Admin
2. If the task was already completed, then click "View all completed tasks"
3. Hover the "Atlassian Marketplace" link

Workaround

Go directly to Atlassian Marketplace instead.