Windows has a feature to hide file extensions for known file types. As a developer, you will want to see file extensions so you know what types of files you are working with. 1. Open Windows Explorer. 2. Click the three dots and select **Options** (or **Folder Options** on older versions of Windows). 3. Under the **View** tab, in the **Hidden files and folders** group, select the option *Show hidden files, folders, and drives*. While you're there, also [[show hidden files]] by selecting the option *Show hidden files, folders, and drives* in the **Hidden files and folders** group and uncheck *Select files with checkbox*.