What type of file should you use to apply a custom theme to a Power BI dashboard?

To apply a custom theme to a Power BI dashboard, you would use a JSON file. JSON, or JavaScript Object Notation, is a lightweight data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. In the context of Power BI, JSON files are specifically structured to contain the theme settings, including color palettes, fonts, and other visual customization options that can be applied to reports and dashboards.

Using a JSON file allows you to maintain the design consistency across your reports and share your custom theme with others. The ability to automate the application of themes through JSON files reduces the effort required to format individual reports, ensuring that they adhere to branding guidelines or personal preferences systematically.

Other file types, such as CSV, XML, and YAML, do not support the specific structural requirements needed for Power BI theme configuration. CSV is primarily for data representation, while XML and YAML are more complex and oriented towards data storage and configuration settings, which are not directly applicable to the customization of themes in Power BI.