365 groups and SharePoint claims

Hi,

After reading the following article, I'm trying to understand what exactly is a "claim":

https://docs.microsoft.com/en-us/sharepoint/dev/transform/modernize-connect-to-office365-group-permissions 

I know "everyone" and "everyone except external users" are also claims (see https://docs.microsoft.com/en-us/office365/troubleshoot/access-management/grant-everyone-claim-to-external-users), so what is the difference between a "group" and a "claim"?

Any insight would be appreciated!