Deprecated repo worck only on FF <= 56 or waterfox
Please try DarkerQuantum

1. Clone or download the repository.
2. Go to about:profiles url in Firefox.
3. Click on show folder.
4. Go to parent folder (C:\Users{User-name}\AppData\Roaming\Mozilla\Firefox\Profiles).
5. Copy/past slimFox repo here: C:\Users{User-name}\AppData\Roaming\Mozilla\Firefox\Profiles.
6. Rename it if you want.
7. Execute firefox.exe -p in terminal or win+r.
8. Click on create a new profile.
9. Choose a name.
10. Check the option by folder.
11. Select slimFox folder.
12. Enjoy!!!

Not yet possible 😢

• Application Update Service Helper
• Classic Theme Restorer
• ColorZilla
• Decentraleyes
• DevEdition theme enabler
• Extension List Dumper 2
• Ghostery
• LastPass
• Location Guard
• Markdown Viewer
• MeasureIt
• Multi-process staged rollout
• No More 404s
• Pocket
• Private Tab
• Stylish
• Test Pilot
• Tracking Protection Experiment
• uBlock Origin
• Video DownloadHelper
• Wappalyzer
• Web Compat
• WOT