Electronic – “folded SMA” package of SMD

I believe the difference is the same as Sot23-5+, in that the 6th pin (Sot-23 can accommodate 6 regular pins) is present, but unused. Regular Sot23-5 has the 6th pin missing.

Based on looking at some other ST datasheets, Sot23-5 and Sot23-5l are used interchangeably. http://www.st.com/web/en/resource/technical/document/datasheet/CD00176077.pdf http://www.st.com/web/en/resource/technical/document/datasheet/CD00079372.pdf

The measurements are exactly the same in any case.

Also, you should always add the part number (AND manufacturer in this specific case) to the question.

The package is called by different trade names by companies,

Lumileds Corp calls them "Barracuda",
while
Osram Opto. calls them "Dragon".

The important feature of the package is a heat-conducting metal center, the "heatsink slug", that can be soldered onto a larger heatsink below:

For details and source, see the chapter on LED packaging of the somewhat-retired LED-related website Light-Emitting-Diodes-dot-org - (note different domain).

See the bottom-left image: Chapter 11: Packaging - Fig 11.5.

A possible reason for not having a clear type code for this package could be that it was not actually a LED package, but just a more generic heatsink-with-extra-plastic-lens.