Ah gotcha problem - yeh where its not referenced like

import { UMB_WORKSPACE_CONTEXT, UmbWorkspaceContextInterface } from "@umbraco-cms/backoffice/workspace";

ie from a package as such, where the one you want seems to be internal and not published as part of a package from what I understand. So you can't reference the context

UMB_USER_WORKSPACE_CONTEXT

May be a context that got overlooked to be made available I am guessing ?! I am sure the friendly crew @Jacob Overgaard or @Niels Lyngsø can advise.

The workspace ones are exported here https://github.com/umbraco/Umbraco.CMS.Backoffice/blob/main/src/packages/core/workspace/contexts/tokens/index.ts

So I am guessing an index.ts file that exports the token needs to live here perhaps?! https://github.com/umbraco/Umbraco.CMS.Backoffice/blob/main/src/packages/user/user/index.ts https://github.com/umbraco/Umbraco.CMS.Backoffice/blob/main/src/packages/user/user/workspace/user-workspace.context-token.ts

I guess this should work from anywhere that you have something that "hosts" the controller, new UmbContextConsumerController(hostingElement,token,callback)

consumeContext<BaseType = unknown, ResultType extends BaseType = BaseType>(
            alias: string | UmbContextToken<BaseType, ResultType>,
            callback: UmbContextCallback<ResultType>,
        ): UmbContextConsumerController<BaseType, ResultType> {
            return new UmbContextConsumerController(this, alias, callback);
        }