TYPO3 Core

In t3lib/class.t3lib_compressor.php at line 292, the external filename is retrieved into the local filesystem, but the filename isn't updated to the local path.

Code change suggestion

Old
$filesToInclude[$key] = $this->retrieveExternalFile($filename);

New
$filename = $this->retrieveExternalFile($filename);
$filesToInclude[$key] = $filename;

Viola! Now, there's no more needing to set the following TypoScript for external JS/CSS files.

includeJSFooterlibs.XYZ.disableCompression = 1
includeJSFooterlibs.XYZ.excludeFromConcatenation = 1