It's not always clear how to report tech related issues. Often times mental notes are taken, akin to "this code needs refactoring", or they're written in code review but without further action taken.
Going down these unstructured routes leads to these issues being forgotten.
I don't think we should define a process here, but give some suggestions for what can be done.
The easiest might be adding #TODO notes as and when these issues are found, and periodically takes some time to go scouting.
Another suggestion might be, for more dire situations, exposing a trello board with all the tech related issues, so it can be seemlessly mixed in with sprints.
Regardless of the approach, the aim is to make sure tech debt is always exposed