src/vs/platform/configuration/common/configurationRegistry.ts/ConfigurationRegistry/registerDefaultConfigurations
class ConfigurationRegistry:	public registerDefaultConfigurations(defaultConfigurations: IStringDictionary<any>[]): void {
		const properties: string[] = [];
		const overrideIdentifiers: string[] = [];

		for (const defaultConfiguration of defaultConfigurations) {
			for (const key in defaultConfiguration) {
				properties.push(key);

				if (OVERRIDE_PROPERTY_PATTERN.test(key)) {
					this.defaultValues[key] = { ...(this.defaultValues[key] || {}), ...defaultConfiguration[key] };
					const property: IConfigurationPropertySchema = {
						type: 'object',
						default: this.defaultValues[key],
						description: nls.localize('defaultLanguageConfiguration.description', "Configure settings to be overridden for {0} language.", key),
						$ref: resourceLanguageSettingsSchemaId
					};
					overrideIdentifiers.push(overrideIdentifierFromKey(key));
					this.configurationProperties[key] = property;
					this.defaultLanguageConfigurationOverridesNode.properties![key] = property;
				} else {
					this.defaultValues[key] = defaultConfiguration[key];
					const property = this.configurationProperties[key];
					if (property) {
						this.updatePropertyDefaultValue(key, property);
						this.updateSchema(key, property);
					}
				}
			}
		}

		this.registerOverrideIdentifiers(overrideIdentifiers);
		this._onDidSchemaChange.fire();
		this._onDidUpdateConfiguration.fire(properties);
	}