I detached a subscription using the GUI at https://console.cloud.google.com/. The detachment went fine. Now I want to delete the subscription and need the subscription ID. I can't find it anywhere in the UI or when I run gcloud pubsub subscriptions list in the built in Cloud Shell terminal.
I expected the subscription to still appear in the subscription list in the project view. I assumed I would then be able to delete it from the UI. I also expected that the subscription would show up when I listed the subscriptions from the cloud shell terminal but it was not in the list.
You are correct that a detached subscription should still appear in the list of subscriptions. A separate delete action is required to remove it.
Is it possible someone else or an automated system deleted the subscription for you?