src/vs/workbench/api/browser/mainThreadCustomEditors.ts/MainThreadCustomEditorModel/isDirty
class MainThreadCustomEditorModel:	public isDirty(): boolean {
		if (this._isDirtyFromContentChange) {
			return true;
		}
		if (this._edits.length > 0) {
			return this._savePoint !== this._currentEditIndex;
		}
		return this._fromBackup;
	}