MediaWiki has an Http class (see includes/HttpFunctions.php) wrapping cURL which falls back to fopen() if cURL is unavailable and throwing a helpful exception if neither is available.
On the other hand Collection uses curl_*() functions directly. This doesn't allow for fallback to fopen() and doesn't display a helpful exception when cURL is unavailable but causes an opaque fatal error which has to be dug up from the error log.
Version: unspecified
Severity: enhancement