Hello
I’d like to begin adding some of my schematic symbols to the Github repository, but how do I decide where to put them?
For example, I’d like to add schematic symbols for the APA102 and WS2812 addressable LEDs, should these go in devices? or a new library?
WS2812 already exists and is in Worldsemi.lib, so I guess it should go in a library named for the manufacturer (which is Shiji Lighting for APA102?).
Actually APA102 seems to be a company called “APA Electronic co. LTD” (makes sense). There are several suppliers who just put their name on the datasheet. This might be the genuine one:
I’m not too sure now, following the datasheet from one of Adafruit’s DotStar (APA102) pages leads you to the original manufacturer that you posted (Shiji Lighting)!
I realised that Shiji Lighting are just a reseller, they have copied their logo onto the data sheet 
My source is https://cpldcpu.com/2014/08/27/apa102/ Normally manufacturers use a prefix according to their company name WS=Worldsemi, AP = APA Electronic, so it makes sense like that.
The devices lip holds only generic symbols (Symbols that do work for many different devices.)
It has the added purpose that we library manager can use the device lib to set the visual style for symbols. This means a symbol that includes a LED, should look similar to the led found in the device lib.
For the addressable LEDs, the LED lib would be the best. (This lib holds specialized LED symbols. The aim is that all but the device lib only hold specialized symbols.)
In future we will remove the manufacturer libs and only “divide” the lib by function.
The resorting will happen with the v5 release. More details https://github.com/KiCad/kicad-library/issues/1402
We also hope to give a better description of what symbols are expected in these new libs. (In the current libs this is not always clear.)
Thanks for the concise answer, I’ll add it to the LED lib (Once I successfully work out how to use git!)