function onJson(err, resolvedContent) {
					if (err) {
						if (resolveContext.log) {
							resolveContext.log(
								`${descriptionFilePath} (directory description file): ${err}`,
							);
						} else {
							err.message = `${descriptionFilePath} (directory description file): ${err}`;
						}
						return callback(err);
					}
					callback(null, {
						content: /** @type {JsonObject} */ (resolvedContent),
						directory,
						path: descriptionFilePath,
					});
				}
@param {(null | Error)=} err error
@param {JsonObject=} resolvedContent content
@returns {void}