The goal of Crash is to be natively compatible with Rhino. But it only currently pushes geometry. It does not include any data. So [CustomObjects](<https://developer.rhino3d.com/api/RhinoCommon/html/T_Rhino_DocObjects_Custom_CustomCurveObject.htm>), [UserStrings](<https://docs.mcneel.com/rhino/6/help/en-us/properties/attributeusertext.htm>) and [UserDictionaries](<https://developer.rhino3d.com/api/RhinoCommon/html/P_Rhino_Runtime_CommonObject_UserDictionary.htm>) are not yet sent by Crash.
Crash 1.4.0-wip does include an API that can be used to make 3rd party plugins multi-user
https://github.com/crashcloud/CrashPluginExample
Crash is a work in progress, so be wary. Always ensure your work is saved and backed-up before testing non-production ready software (such as Crash!) with your project files.
It is one of the terms used to refer to a group of Rhinos.