"Public Broadcast" is a style under Non-Music, mainly with voice-overs, ads, track mixing, etc.
Be careful with releases made for distribution to AFRTS (American Forces Radio and Television Service) stations:
'Transcription' covers the licensing end of the release. It's like the Promo format tag.
'Public Broadcast' covers the content end. It is a semi-meta style in which the recording can contain music, PSA's, promotional material, interviews, and interstitial announcer spoken word sequenced for contiguous broadcast (or a recording of such).
Some releases are both, some releases are either or neither. There's definite overlap. The modern equivalent would be a (downloadable) podcast, which Staff has okayed for use under this tag.