Please tell me what is the role of *= operator in below piece of code
@If(@UserRoles *= "[admin]" ; "" ; @Return(""));
It is formula language used in lotus notes databases.
That is a Permuted Equal.
if a="this" or a="that" or a="other" then....
So this code sets to "" if is admin, otherwise it bails with a "".
Agree with @rhsatrhs, this is unclear and should be written using a normal =.
Here is a link to the Permutations operators official documentation.