Learn Finnish: Suunnitelma on hyllytetty.

It comes from the verb hyllyttää, meaning to shelve or put on a shelf. This is a great example of Finnish word derivation: it is built directly from the noun hylly (shelf). In a business or administrative context, it means to postpone or suspend something, just like 'to shelve' in English.

Why is it on hyllytetty instead of hyllytettiin?

Hyllytettiin is the simple past passive ('was shelved'), focusing on the action happening in the past. On hyllytetty is the perfect passive ('has been shelved'), which acts almost like an adjective here. It describes the current state of the plan: right now, its status is 'shelved'.

How would we change this to the negative potential passive, meaning 'The plan is probably not shelved'?

You would say Suunnitelmaa ei hyllytettäne. Notice two things: first, we use the negative word ei followed by the passive potential stem hyllytettäne. Second, the subject changes from the nominative suunnitelma to the partitive suunnitelmaa because negative passive sentences require a partitive object.

Why is suunnitelma in the nominative case here?

In standard Finnish affirmative passive sentences, an object that represents a whole, countable thing takes the nominative case (the basic dictionary form). If this were a negative sentence, such as Suunnitelmaa ei ole hyllytetty (The plan has not been shelved), the object would flip to the partitive case.