Restricted users are able to make any changes within the Portfolio plan, including but not limited to manipulating issues, their estimates, priorities and schedules, as well as teams, releases, etc. The only restriction is that these changes cannot be committed back to Jira.
Restricted users are still able to see and interact with the "Review and commit changes" dialog. They can review and revert their changes in Portfolio, however the button to commit to Jira is removed.
Access restriction overrides "native" Portfolio user permissions. Even if users have editor access in plan or global Portfolio configuration, they will not be able to commit changes. The restriction affects all plans, currently there is no way to only apply it for some (but not all) plans.