Its a unit in the IDE project itself (in the IDE folder). Probably ide/etmessageframe but I am not sure (that file was recently changed for a feature related to the messages, so probably...
And I don't know how much is in that unit. E.g. the organisation of the data to be displayed, I don't know where that is.
And likely it has references to other units in the IDE.
You would have to copy it, and clean it.
And just for info, its GPL, not LGPL (as is the IDE itself)