difference between role and group?

English:Fess
1

(from github.com/AllenHan5)
Hello expert,

FESS defines both. Are there any difference between them?
Thanks

2

(from github.com/marevol)
Functionality for them is the same.
To support various identity systems, Fess defines them.

3

(from github.com/AllenHan5)
Thank you so much for the clarification, @marevol !!