Just reading through the code it appears that this parameter will always appear in the link, I'm not entirely sure why though. I can understand why the value would get appended given
hasStoreId returning true, but if no store is specified, the current store is used. Why force a link onto a store it's currently on? Is there a situation in which this actually does something useful?
For context, I was looking into the code because a site we've been asked to review, is using this widget. The existence of this specific query parameter seems to be making Phoenix_VarnishCache generate an EXTERNAL_NO_CACHE cookie which seems to force the client to avoid the cache. The expiration date on this cookie is 3 hours in the future, and the expiration appears to be renewed upon each request. I'm yet to look into why this cookie might function in this manner, it seems odd to say the least. I can't swear that the module hasn't been modified however, so it might not be default behaviour for the module.