LICENSE: Seems like the easy part https://github.com/apache/incubator-pekko/blob/main/LICENSE is a clean copy of the ASF license. Might have to paste in that protobuf license.
NOTICE: Will have to be compiled. https://www.apache.org/legal/src-headers.html#notice And will have to contain a section for lightbend. Source Headers: This is where it get's complicated. As suspected, the Lightbend header will need to stay in place. https://www.apache.org/legal/src-headers.html#3party https://github.com/apache/incubator-pekko/blob/main/akka-actor/src/main/scala/akka/AkkaException.scala#L2 But I'd think the whole code base will "evolve significantly" over time, so something should be added there, yet just writing: Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. would obviously be wrong.
