Well, if you get an USB-C Power supply that says it's USB-PD or USB 3.1, then they might not have the fallback, as it only needs to support USB-PD and USB3.1 then.
They made a real mess out of USB-C, to be honest.
UL doesn't make sense. It's not needed and costs a lot of money, so unless you think customers want to pay 100 USD+ for this adaptor, it's totally overkill. As you mention: It's optional and not needed. It makes sense for products that are being sold in millions of quantities, but not for something like that. You're free to donate a UL certification, if you like
Why should I put CE and FCC on the product page? I don't have these for ANY products in my shop, and Amazon or any other online shops also don't list CE / FCC. Probably because it's not even allowed to sell them without these, these are mandatory.
And why do you think the logos are not on the box or the product? They are both on the retail box as well as on the product AND the DoCs are included in the packaging as well.
Please don't assume anything you don't even know.
Besides, the ColUSB is not a DC adapter, it's a simple low-voltage power converter.
Yes, DC adapters can potentially be dangerous because these operate with 110 / 220V.
In Germany, these need additional safety tests and certifications, which are very expensive. That's the reason we designed a power converter and not a DC adapter. A low-voltage device operating at 5V without any battery included is NOT dangerous and doesn't need these safety tests.
The ColecoPlug retail box pictures in this thread and the pictures of the ColecoPlug in this thread do not have the CE and FCC logo, and that is why I mentioned the logo does not appear in the specs or pictures. Now if I order the actual finished product and it has the CE and FCC logo then that is real cool. I am just use to looking at pictures of adapters on Amazon and other websites that have those official safety logos on the product.