it allows you to put expiration on your code comments.
a comment can expire by e.g. a github, jira or youtrack issue-url. expiration dates and composer version constraints also work.
Today I collaborated with ondrey on a fix for #phpstan which improves a previous performance fix, which caused perf regressions in a #laravel edge-case.
The new fix allows a 2-3 seconds instead of 2-3 minutes analysis in all mentioned cases.