src/vs/platform/configuration/common/configurationRegistry.ts/ConfigurationRegistry/registerDefaultConfigurations
class ConfigurationRegistry:	public registerDefaultConfigurations(configurationDefaults: IConfigurationDefaults[]): void {
		const properties: string[] = [];
		const overrideIdentifiers: string[] = [];

		for (const { overrides, source } of configurationDefaults) {
			for (const key in overrides) {
				properties.push(key);

				if (OVERRIDE_PROPERTY_REGEX.test(key)) {
					const defaultValue = { ...(this.configurationDefaultsOverrides.get(key)?.value || {}), ...overrides[key] };
					this.configurationDefaultsOverrides.set(key, { source, value: defaultValue });
					const plainKey = getLanguageTagSettingPlainKey(key);
					const property: IRegisteredConfigurationPropertySchema = {
						type: 'object',
						default: defaultValue,
						description: nls.localize('defaultLanguageConfiguration.description', "Configure settings to be overridden for the {0} language.", plainKey),
						$ref: resourceLanguageSettingsSchemaId,
						defaultDefaultValue: defaultValue,
						source: types.isString(source) ? undefined : source,
					};
					overrideIdentifiers.push(...overrideIdentifiersFromKey(key));
					this.configurationProperties[key] = property;
					this.defaultLanguageConfigurationOverridesNode.properties![key] = property;
				} else {
					this.configurationDefaultsOverrides.set(key, { value: overrides[key], source });
					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, defaultsOverrides: true });
	}