Recently the add-on was removed by Mozilla, because there were users other than ViewGrip who downloaded it and they complained that they couldn’t use this add-on.
We know that this add-on was developed only for ViewGrip users and only viewgrip users can use the features of the add-on, We have notified mozilla that this add-on is only for ViewGrip users, and we have decided not to publish it on the mozilla site.

Add-on details:
Add-ons only work for ViewGrip
Add-ons do not contain any element of damage to the browser
Add-ons do not contain malicious files
Add-ons do not contain tracking code

Add-on permissions:
Access your data for sites in the youtube.com domain
Access your data for sites in the viewgrip.net domain
Access your data for sites in the google.com domain
Access your data for www.youtube.com
Access your data for www.viewgrip.net
Access your data for youtube.com
Access browser tabs

There is nothing to worry about with our add-ons, we are always principled for the best for users, please download the add-on here

Regards