Undocumented Forge query key predicates?

I have been exploring the Forge storage capabilities and options to query stored values.

The Forge query documentation only talks about the STARTS_WITH key predicate. However, if I inspect the Typescript type declarations, there are two additional key predicates, NOT_EQUAL_TO and IN.

Can anyone explain if these additional predicates are supported but not documented or if they should not be used?

Typescript type declarations: storage-adapter.d.ts
export declare type Value = string;
export interface StartsWith {
    condition: 'STARTS_WITH';
    value: Value;
export interface NotEqualTo {
    condition: 'NOT_EQUAL_TO';
    value: Value[];
export interface In {
    condition: 'IN';
    value: Value[];
export declare type Predicate = StartsWith | NotEqualTo | In;
export declare type Condition = Predicate;

Hi Tobias

Unfortunately these predicates are not available to developers.

We’re currently exploring other predicates to improve querying power.