igpapi — Instagram private API Simulator for Node.js (API reference) 4.14.0
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    Variable ReelsViewerChainingSchemaConst

    ReelsViewerChainingSchema: Struct<
        {
            chainingPosition: optionalKey<Union<readonly [Number, String]>>;
            chainingSeedMediaId: optionalKey<String>;
            chainingSessionId: optionalKey<String>;
            clientPosition: optionalKey<Union<readonly [Number, String]>>;
            mediaPctWatched: optionalKey<Union<readonly [Number, String]>>;
            rankingSessionId: optionalKey<String>;
            storyRankingToken: optionalKey<String>;
        },
    > = ...

    The viewer's chaining session as a screen's state holds it: what its like and its comment name. The viewer resolves it from its input once per visit (the two session ids it lacks are minted there, the seed and the positions are derived from the reel and its list) and every reel reads it as its host's state, never a copy stamped on the entry.