Ads.TextRefPage
To upload the Ads.txt file, or app-ads.txt file
“In the text block, name your file. This does not have to match the actual file name. Just name it something you’ll recognize later on.
Highlight what you just typed and click on the button to add a link. Then, click on the gear icon in the popup window. In the lefthand menu of the popup window, click on File. Next, click Upload File to upload your file. Click on your file name to select it and then toggle “Open in a New Window” on. Finally, hit Save > Apply.”
Note that after the file is uploaded.. we have set a URL mapping to the file via these instructions:
More Instructions here, that seem to be even more up to date