Forma'd warframe is level 30 in Railjack mission. Noice!

[RazerXPrime]

So I put a forma on my Nezha prime, reverting it back to level 0. Took it into a Railjack mission and presto he's level 30. I had access to all my abilities too as if they were max rank.

Screenshots:

As you can see he's level 30. Abilities are unlocked and there's this neat number 30 next to his name.

 

And here's the mission complete screen:

As you can see here he's actually level 6 if taken bonus affinity into account. Still, I was able to use all my abilities freely.

Also lol at mandatory tag.