Baez and Crans in their paper on 2-Lie algebras refer to adjoint representations of Lie 2-groups but don't say much, as far as I can tell, except to say that such a representation acts on a 2-Lie algebra. Where can I find a description of the adjoint representation of Lie 2-groups?

Is there any connection with representations of Lie groupoids up to homotopy?

Baez and Crans in their paper on Lie 2-algebras refer to adjoint representations of Lie 2-groups but don't say much, as far as I can tell, except to say that such a representation acts on a 2-Lie algebra. Where can I find a description of the adjoint representation of Lie 2-groups?

Is there any connection with representations of Lie groupoids up to homotopy?