Thinking back, I believe we've had these yellow LEDs for a long time already as "indicator" type LEDs on instruments or control panels or similar things.
I was thrown off by the "amber" orange ones, which are made from GaAsP without the Nitrogen doping, being the one's suggested by astronomers and environmentalist to reduce light pollution even further by operating in the range between 590nm to 625nm. Since I hadn't seen those before being widely used, I presumed that there must be some considerable downside to them.
But even these already seem to be widely available for not much higher prices than comparable other colors. Though some of the examples that I've seen seem to use orange phosphors implying that they still have a blue/UV LED underneath, which then would also require to filter whater of those wavelengths leak through.
Like this one here
https://www.amazon.com/Melphan... (not intended to be advertisement, just a reference) has what looks like an orange phosphor or at least an orange diffuser in front of it. A genuine GaAsP wouldn't need that "orange" filter.
Investigating further, I found a data sheet for the "3014 LED" that are used in there.
https://lumileds.com/wp-conten... on page "5 (6 of 25)" (according to the PDF reader) is a spectral power distribution showing a big peaks around 450nm (blue). This is something that would have to be avoided.
I'll look further into it, because now I want to buy one of those, but need to find the right type first.