src/vs/workbench/contrib/customEditor/common/customEditorModelManager.ts/CustomEditorModelManager/get
class CustomEditorModelManager:	public async get(resource: URI, viewType: string): Promise<ICustomEditorModel | undefined> {
		const key = this.key(resource, viewType);
		const entry = this._references.get(key);
		return entry?.model;
	}