Include which illegal character was found in a faulty variable and in which attribute

[phackstock]

Currently, we only get the information that an illegal character was found, not which one which makes trouble shooting unnecessarily tedious.
As an example, I get this output for one of our old repositories:

...
  1625. Unexpected character in variable: 'Final Energy|Non-Energy Use'. Check for illegal characters and/or if tags were spelled correctly.
  1626. Unexpected character in variable: 'Final Energy|Non-Energy Use|Biomass'. Check for illegal characters and/or if tags were spelled correctly.
  1627. Unexpected character in variable: 'Final Energy|Non-Energy Use|Coal'. Check for illegal characters and/or if tags were spelled correctly.
  1628. Unexpected character in variable: 'Final Energy|Non-Energy Use|Gas'. Check for illegal characters and/or if tags were spelled 
...

EDIT:
After bilateral discussion with @dc-almeida, I understand the above check also affects attributes and not only the variable name. This should also be reflected in the error message.
Something like:

...
  1625. Unexpected character ';' in variable.description of: 'Final Energy|Non-Energy Use'. Check for illegal characters and/or if tags were spelled correctly.
...