My demo build got rejected for the following reason:

Application Review Results For ‘no signal Demo’

We encountered some issues while testing a build of ‘no signal Demo’.

Please read and follow the instructions:

• Please note that we are currently unable to verify the implementation of your app’s Linux/SteamOS support due to our work-from-home status. Be sure to thoroughly test the app through Steam on a fresh Linux machine, to ensure all dependencies have been met and the app functions as intended.
• Failure: Your build has failed our review because it contains a call to action to purchase products from a non-Steam website. The ‘Credits’ menu includes a link that brings the user to a website where they purchase 3D assets directly. https://markom3d.gumroad.com/l/Free3DKitbash If your app has a call to action to buy products, the link provided must use Steam and Steam Wallet as the only means of payment.

Apparently, even though since the link is on a credits page, since it goes to a page where you have a choice of either the free kitbash assets or the paid kitbash assets it is considered a call to action to buy products.

I think this is ridiculous, because my intention is to “cite my sources” by sharing where some of the items I used in the game comes from, and there is no possible benefit for a player to own the assets when playing the game, nor am I asking them to acquire the assets. Also, as Outfrost pointed out, does this mean saying that the game was made with RPGMaker while linking to the RPGMaker website considered a call to action to buy products? There is no free version of RPGMaker after all.