Styled+ for Firefox
The 'Stealth Mode' software enhances privacy by darkening website content (95%) when the cursor is moved away from the browsing space on desktop. Takes only 10 seconds to activate.
byfrankell 
Dock Styles Series for Styled+
This app operates within Firefox profile, embedding images and codes locally to enhance browsing without using internet bandwidth. It allows customization without requiring website data hosting, preventing silent connections.
ColorsCode for Firefox
This app works within Firefox profiles, with images and codes embedded locally. Firefox fans can personalize their browsing without using internet bandwidth.