DWG files can have a coordinate system assigned. It would be helpful if ACadSharp can read the definition of the coordinate system.

In the Autodesk AutoCAD API the coordinate system is available as property of the database:
GeoLocationData geolocation = t.GetObject(db.GeoDataObject, AcDb.OpenMode.ForRead) as GeoLocationData;
Preferably ACadSharp stores the coordinate system as property of document because ACadSharp doesn't has a database.

The XML definition of the of the coordinate system is available under DXF code 'GEODATA'. If you use the method this._textReader.ReadVariableText() you get the XML definition of the coordinate system.