What is a shame is that due to the dynamic nature, the release records of old releases on PMI are changed after release and review. This is not a Titan specific issue - all the old CDT release records will be affected too if CDT gets archived.
This is an example of a feature that really seemed like a great idea when we created it seven years ago and the prospect of moving away from Bugzilla was very foreign. The convenience of it was better that what we had previously been doing: an escaped Bugzilla URL embedded in an XML-based plan document that was converted to HTML via XSLT (this was a nightmare for everybody other than the Eclipse Platform team who seemed to like it). I'll admit to having been rather proud of the implementation.
Ultimately, I think that we're all better served by tools that help us generate durable artifacts that we can store directly in the source repository (this is probably also true for GitHub/GitLab issues). It should be a relatively simple matter to generate a change log based on the PMI records. I'll see what I can come up with.
Wayne