@babel/helper-create-class-features-plugin

const FEATURES: Readonly<{
    fields: number;
    privateMethods: number;
    decorators: number;
    privateIn: number;
    staticBlocks: number;
}>;

buildCheckInRHS: (
    rhs: types.Expression,
    file: File,
    inRHSIsObject?: boolean
) => types.Expression;

buildNamedEvaluationVisitor: (
    needsName: (path: NodePath) => boolean,
    visitor: (
        path: NodePath,
        state: PluginPass,
        name:
            | string
            | types.Identifier
            | types.StringLiteral
            | types.NumericLiteral
            | types.BigIntLiteral
    ) => void
) => VisitorBase<PluginPass>;

createClassFeaturePlugin: ({
    name,
    feature,
    loose,
    manipulateOptions,
    api,
    inherits,
}: Options) => PluginObject;

enableFeature: (file: File, feature: number, loose: boolean) => void;

injectInitialization: (
    path: NodePath<types.Class>,
    constructor: NodePath<types.ClassMethod> | undefined,
    nodes: types.ExpressionStatement[],
    renamer?: (visitor: Visitor<RenamerState>, state: RenamerState) => void,
    lastReturnsThis?: boolean
) => void;