Traceability has been discussed in software engineering since the start. Already at the pioneering NATO Working Conference on Software Engineering in 1968, Randall argued that a developed software system should “contain explicit traces of the design process”. The most commonly cited traceability definition is tailored for requirements: “the ability to describe and follow the life of a requirement, in both forwards and backwards direction” (Gotel and Finkelstein, 1994). I like the definition presented in the traceability book edited by Cleland-Huang et al. (2012) stating that traceability is “the potential for traces to be established and used” and a trace link is “an association forged between two trace artifacts” (e.g., dependency, refinement or conflict). During my PhD studies, a lot of my work was related to understanding and supporting traceability.