Usage:
labelopt info attribute

Labelopt info controls what information is shown in subsequently displayed atom labels. Labels already shown are not changed; if attribute values change, the labels must be displayed again to reflect the changes.

The attribute can be any atom attribute, whether built-in or created during use of Chimera:

• name (default) - atom name with any alternate location ID appended
• residue - model number, residue name, and residue identifier (number.chain)
• element
• idatmType - atom type
• charge - partial charge such as assigned by addcharge
  (etc.)