Spec updates (to 1/31): predicted outputs, developer message #1519

Job	Run time
build	1m 17s
azure_build (ubuntu-latest, net8.0)	1m 43s
azure_build (macos-latest, net6.0)	1m 27s
azure_build (windows-latest, net462)	2m 37s
	7m 4s

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