ls command: What does the @ in file mode mean, and how to get rid of it?
From the ls manual (man ls) section The Long Format


  If the file or directory has extended attributes, the permissions field printed by the -l option is followed by a '@' character.


You can then display the extended attributes with -@


  -@      Display extended attribute keys and sizes in long (-l) output.


To manipulate extended attributes you can use the xattr command. See for example How do I remove the extended attributes in Mac OS X or Dealing With Extended Attributes on OS X