How to check the access levels of a single user in team shared pipelines?

In My account menu, select Users tab. This will present a list of all the users in your Gearset team.

You should see the Users tab open with a preview showing all the users.

Select a team Member by clicking on this button:

This will display user's profile. Scroll down a bit down to Pipelines & CI jobs section - here you can see all the team-shared resources (Pipelines & CI jobs) that selected member has access to.

In the above example you can see that the member has access to pipeline named AWS Team shared and when you expand the down arrow, you can see the list of CI jobs and their access level.

And this article will tell you how to assign permissions to multiple pipelines and ci jobs in bulk to a single user.