[Luxter]

Uwon, many thanks, brilliant!!
That's absolutely priceless.

Upon quick reading:

(52) A daytime running lamp may be optically combined with a front fog lamp that conforms to SAE Standard J583, Front Fog Lamps (June 1993), or to paragraphs 3, 4.2, 4.3, 5 and 6 of ECE Regulation No. 19, Uniform Provisions Concerning the Approval of Motor Vehicle Front Fog Lamps, Revision 3 (March 2, 1993).

I believe that Porsche fog lights do meet all mentioned regulations (issued in 1993).

Problem solved without guessing or assuming anything.