This code checks if the user has somehow posted a user deletion for a user that has "system" scope. If so, then the delete iscnot done and an input error is displayed. Note that in normal use the user manager page does not display a delete button for "system" users, so normally this does not happen - only if the user manually messes with the $POST variables.
Related issues
Bug #5294: System users and groups not fully protected from deletion
Redmine #5294 Do not delete a system user
This code checks if the user has somehow posted a user deletion for a user that has "system" scope. If so, then the delete iscnot done and an input error is displayed.
Note that in normal use the user manager page does not display a delete button for "system" users, so normally this does not happen - only if the user manually messes with the $POST variables.