how to summarize all the issue one person has worked on across projects?

[Nic Brough -Adaptavist-]

Depends on how you define "worked on"?  For example, can you say that they were assigned to the issue at some point?  Or just updated it for some reason?  Or that they must have logged work?  Something else?

(All of those are valid ways of working, but they need different ways to identify the issues, hence the need to ask!)