Within the ‘Activity’ section of a ticket, comments are visible on the new bugtracker site. ‘History' and ‘Transitions’ (as well as an ‘All’ tab) were present on the old bugtracker site but are not on the new site.
Old site example: https://bugs-legacy.mojang.com/browse/MC-2836
New site example: https://report.bugs.mojang.com/servicedesk/customer/portal/2/MC-2836
Jira Service Desk does not support these fields. They are still present on the internal Jira however.