pub const DISTILL_BACKEND_VALUES: [&str; 2];Expand description
Provider backends apr distill --backend accepts.
Unlike the two above this one was NOT silently accepted: distill::run()
(commands/distill.rs:464-503) matches on it before any I/O and returns
ValidationFailed naming both valid values, covered by
distill_run_unknown_backend_errors. Wiring the same list into clap is
defence in depth and makes --help advertise the set, but it closes a
help-text gap, not a silent-wrong-backend defect. The runtime check stays.