In Dynamics 365, you can view the security diagnostics for any page from GUI without opening visual studio (or opening AOT like  AX 2012)

For Example,  all sales order page

Go to Accounts receivables/orders / all sale orders


 click security diagnostics under  the options tab


you can see all security diagnostics that related to this page (roles-duties-privileges)

you can show/hide AOT object name


note:: a new functionality added to this point in Dynamics 365 

you can assign the security diagnostics to any user from this page (no need to go system administration module like 2012)

just click, add roles to user button



click manually assign/exclude users


click assign role or exclude based on your demand.

 In AX 2012, you must open this form in design mode to view security diagnostic as the below 



Thanks.