View and manage the files in your Google Drive: This seems excessive, but it’s strictly used to create Online Rubrics, to search for and display rubrics, and to import rubrics. The broadness of this permission is necessitated by Google. As far as I know, there’s nothing I can do about it.
Know who you are on Google: Another permission Google requires in authenticating you. I don’t make use of or store any personal information.
View your email address: Used in authenticating you, as well as the email functions of this add-on.
View and manage your spreadsheets in Google Drive: See explanation for the first.
View and manage data associated with the application: These are the options that you choose as you set up the rubrics. No personal information, including students’, is visible on my end.
Allow this application to run when you are not present: As far as I can tell, the only time this is used is when first installing the add-on. Otherwise, this add-on doesn’t run without you.
Send email as you: Used to send email rubrics
Manage your Google Classroom classes, class rosters, view the email addresses of people in your classes: Used to import rosters from Google Classroom.
View the profile photos of people in your classes: Online Rubric does not access, store, or use photos – this request is incidental to pulling roster information.