The themes are provided in 3 different packaging all following Microsoft guidelines:
For Classic Experience:
- Farm Solution, folder for Farm environments
- Sandbox Solution, for Sandbox environments.
For Modern Experience:
- Modern Solution, Modern SharePoint.
After unzipping your Theme package, you will find three folders, a Farm Solution, Sandbox Solution and Modern Solution. Depending on the SharePoint configuration you may install all the packages.
Farm Solution (Classic SharePoint) 📁
── res 📁
Sandbox Solution (Classic SharePoint) 📁
Modern Solution (Modern SharePoint) 📁