src/vs/platform/contextkey/common/contextkey.ts/RawContextKey/constructor
class RawContextKey:	constructor(key: string, defaultValue: T | undefined, metaOrHide?: string | true | { type: string, description: string }) {
		super(key);
		this._defaultValue = defaultValue;

		// collect all context keys into a central place
		if (typeof metaOrHide === 'object') {
			RawContextKey._info.push({ ...metaOrHide, key });
		} else if (metaOrHide !== true) {
			RawContextKey._info.push({ key, description: metaOrHide, type: defaultValue !== null && defaultValue !== undefined ? typeof defaultValue : undefined });
		}
	}