New answers tagged roles
Site owner can not view site from Viewer's angle. Your given permission must be appeared whenever you login in a site. When I test permission in sites, I used to create several users like Editor, Reader, Admin and so on.
OOTB he can't, the best option is to have a test account(s) for this purpose where you can log into a PC or run browser sessions as that dedicated test account and get the same experience as the other users. He only has the option to go through lists and libraries looking for broken permissions and doing effective permission lookups.
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