Was able to find it like this, which might be a horrible way to do it, but seems to work at least. Wasn’t able to look at effects inside effect chains though, so made a separate post about that.
function checkEffectForOcclusionParameter(effect) {
if (effect.automators && effect.automators.length > 0) {
for (var i = 0; i < effect.automators.length; i++) {
var automator = effect.automators[i];
if (automator.automationCurves && automator.automationCurves.length > 0) {
for (var j = 0; j < automator.automationCurves.length; j++) {
var curve = automator.automationCurves[j];
if (curve.parameter && curve.parameter.presetOwner && curve.parameter.presetOwner.name === "Occlusion") {
return true;
}
}
}
}
}
return false;
}