PUP.Optional.Wajam is the detection name for Wajam, a browser add-on marketed as a “social search.”
This detection was often seen in combination with Crossrider browser hijackers and Multiplug adware. It was named after the registry keys and folders it added on affected systems:
Crossrider, Multiplug, and GlobalUpdate were all installed by bundlers.
Malwarebytes removes PUP.Optional.GlobalUpdate completely. No further cleanup is required.