Do all game items have a 15% selling fee on Steam Community Market?

[Gremlin]

I know that there is game-specific fees for Valve created games (extra 10%).

So I was going to sell a Rust item on the market, and I noticed that I pay the same exact 15% fee as Valve made games. I tested with other games and I still pay the 15% fee.

Is there something I'm missing? The market clearly states there is a 5% fee for items, then 10% for Valve made games.

[Cristal Maiden ™]

Not all games, Black desert ( as example ) - If U buy in-game items, U can't sell them in Community market or trade
Once wasted your money with their "useful" items, it remains wasted 4life

[JJ, Professional Fool]

The 15% comes from using the service of the marketplace. In-house all of it. Even if not a valve server or developed title the objects being sold is via steam marketplace, a subsection of steam services. 10 goes to valve because their marketplace, 5 goes to the dev or host of title, like rust admins, and the rest you keep or pay.

This is moot for all games with 3rd party currencies, like red beans for firefall or kikao coins for BDO, plat for warframe items, yadda. yadda.

If the item can be marketable it belongs to valve, this is why we pay into the fee. To use the service.