There's a protobuf-grammar repo with an open PR for a context-free grammar. You could probably use that to get a list of keywords.
You can find it here: https://github.com/ObsidianMinor/protobuf-grammar/blob/0bc288b63405bad84202be670b03d169a148fdee/spec/grammar.ebnf -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/protobuf/008a2713-f0f9-4980-a573-0d69a8f5e108%40googlegroups.com.
