Type Alias AnalyserChannelFact

AnalyserChannelFact: {
    [K in keyof typeof CHANNEL_CONTRACT_TABLE]: typeof CHANNEL_CONTRACT_TABLE[K] extends {
        needsAnalyser: true;
    }
        ? K
        : never
}[keyof typeof CHANNEL_CONTRACT_TABLE]

The facts whose machine READS THE ANALYSER LANE — derived from the ChannelFactDecl.needsAnalyser column, at the type level, so the union cannot drift from the table. Add the column to a row and this union grows; delete it and it shrinks.