Glossary
Protocol Buffers (protobuf)
Protocol Buffers (protobuf) is the binary format of most Biome record payloads. Wire format basics, and why schema-less decoding stays ambiguous.
Protocol Buffers (protobuf) is a compact binary serialisation format from Google. Most SEGB records in Biome carry a protobuf message as their payload. On the wire, each field is written as a tag, which combines a field number and a wire type, followed by the value: a variable-length integer, a fixed 32-bit or 64-bit value, or a length-delimited block.
Field names exist only in the schema, and Apple does not publish its Biome schemas. Parsers such as mac_apt therefore decode payloads without a schema (using blackboxprotobuf) and rely on field numbers mapped by community research, for example App.InFocus field 3 = status and field 6 = bundle ID.
Schema-less decoding is ambiguous: a length-delimited field can be text, raw bytes or a nested message, and a 64-bit value can be an integer or a double. Treat unmapped fields as unknown rather than guessing. See the Biome SEGB file format.