See Who Changed a Role's Permissions and When

There are two ways to see how a role's permissions have changed over time:

• On the Setup > Users > Roles tab, open a role and click Change Log. A side panel opens with the full history of that role, including which permissions were added or removed, who made each change, and when.
• To review changes across all your roles at once, use the Role Change Log data source to build a report. It shows the same history in a format you can filter and export, which is handy for audits.