seq.count
An expression node, provided by Rulealize.Plugin.Sequence.
Form
{
"op": "seq.count",
"source": <expression:Sequence>,
"as": "<name>", // optional
"where": <expression:Boolean> // optional
}What it does is in that plugin's specification, which ships with the plugin and changes when it releases — read it.
Add it
dotnet add package Rulealize.Plugin.Sequence