The supplemental materials for our paper are organized as follows: * `Interview Questions.pdf`: The main questions asked during the interviews. * `Interview_questions_with_followups.pdf`: Interview questions with all the follow-ups asked to each participants. * `Follow-up Interview Questions.pdf`: The main questions asked during the follow-up interviews. * `IRRCodebook.xlsx`: The dataset used to test the Inter-Rater Reliability (IRR) between the two coders. It contains three sheets: C1 for coder 1, C2 for coder 2, and CodeNumbers to match the themes to the numbers. The quotes from three interviewees are paraphrased to protect anonymity and comply with the IRB protocol, which prohibits the release of participant data. * `CohensKappa.ipynb`: The code to calculate the IRR using Cohen's Kappa on the IRRCodebook.xlsx dataset. * `Theme definitions.pdf`: Provides a comprehensive explanation of each theme used in the IRRCodebook and for data analysis by the coders. * `Literature.xlsx`: A collection of relevant literature on studies investigating the role and capabilities of visualization in differential privacy implementations. * `DPUnderstanding.xlsx`: A detailed breakdown of differential privacy expertise levels, their definitions, and the questions users with these levels of understanding can answer.