src/vs/platform/contextkey/browser/contextKeyService.ts/ConfigAwareContextValuesContainer/getValue
class ConfigAwareContextValuesContainer:	override getValue(key: string): any {

		if (key.indexOf(ConfigAwareContextValuesContainer._keyPrefix) !== 0) {
			return super.getValue(key);
		}

		if (this._values.has(key)) {
			return this._values.get(key);
		}

		const configKey = key.substr(ConfigAwareContextValuesContainer._keyPrefix.length);
		const configValue = this._configurationService.getValue(configKey);
		let value: any = undefined;
		switch (typeof configValue) {
			case 'number':
			case 'boolean':
			case 'string':
				value = configValue;
				break;
			default:
				if (Array.isArray(configValue)) {
					value = JSON.stringify(configValue);
				} else {
					value = configValue;
				}
		}

		this._values.set(key, value);
		return value;
	}