Ask HN: How does X "Show 35 Posts" work?

Has anyone noticed that on X's(Twitter before) “For You” tab, every time there are new posts, it always shows “Show 35 Posts” or multiple of 35, such as 70, 105? Where does this number 35 come from? Any story behind this?

Example: https://www.pixelstech.net/fun/1106-The-Magic-of-X%26%23039s-Show-35-Posts