Attachments in New Tab plugin does not need any configuration. Immediately after installation, in Jira Service Management issue details, a new link “Twinit Attachments“ will appear in the right ribbon:
Clicking the link will open plugin sidebar with the list of all the attachments:
Clicking a specific attachment will open the file in a new tab:
Due to a security measure introduced since Chrome version 88, to open an attachment in a new tab, instead of left mouse click, middle mouse click or Ctrl+left click should be used.