Review for Session Manager by amba2
Rated 5 out of 5 stars
This is how you reenable Session Manager after it has been disabled by firefox 57:
Optional: Backup user profile, by copying the folder on hamburger menu-> '?'-> 'Troubleshooting Information'-> 'Open Folder'-> go up one level and copy the folder with random letters and numbers.
1. Install a version of firefox that supports "legacy" extensions, like FF ESR 52.
2. Run the browser. If Session Manager is still disabled, go to this page, Click "Add to Firefox" and install Session manager
To create your own collections, you must have a Mozilla Add-ons account.