syntax_data: {"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":"opt(Stable,"}]}
source_snippet:         opt(Stable, Flag, "", "test", "Build a test harness", ""),
context_before:         ),
context_after:         opt(Stable, Opt, "", "target", "Target triple for which the code is compiled", "<TARGET>"),