If you are a git user, you can install the theme and keep up to date by cloning the repo:
git clone https://github.com/dracula/aseprite.git
Notice that in order to actually install and activate the theme, you would have to zip the directory.
You can also download using the GitHub .zip download option and unzip them.
- Open Aseprite
- Navigate to Edit ⇒ Preferences... ⇒ Extensions
- Click Add Extension
- Navigate to the downloaded extension .zip file
- Select it
- Click OK
- Navigate to Edit ⇒ Preferences... ⇒ Theme
- Select the theme from the list
- Click Select
- Theme will be applied immediately