STOCHASTIC_RSI: IndicatorDescriptor = ...

Stochastic RSI — where RSI sits inside its own recent range, which turns a slow-moving oscillator into a fast one.

The reference passes rsi1 in as all three arguments of stoch, so the window is the RSI's high and low rather than price's, and every warmup adds to the one before it: 14 bars for the RSI, 14 more before the stochastic window is full of real RSI values, then two SMAs. First K lands at index 29 on the defaults and D two bars later.