https://www.kaieteurnewsonline.com/

[Lunokhod]

https://www.kaieteurnewsonline.com/
I have seen issues here before with the animated newspaper display at the top left of the page. Toggling webgl.disabled to true in about:config would give a fallback display with sliding pages instead of turning pages, but toggling that no longer does anything. Instead, for me at least, also tested in a fresh profile, that part of the page is simply not shown at all. But it is shown in Firefox and Chromium.
(I'm pointing this out for general interest and bug reporting rather than it being vital that I can personally view it in Pale Moon as opposed to using another browser or finding the stories elsewhere on that website.)

[vannilla]

Looking at both the console and the page's DOM, it appears to be related to CSP.
The panel that is supposed to display the e-paper is actually an iframe inside another iframe and usually this kind of containerization is placed under strict rules to avoid various exploits.
Naturally the second iframe has content entirely dependant on scripts, so if the resource loading and execution is blocked nothing is created.

[Moonchild]

No, it seems to be a css issue that collapses the display element. The wrapper iframe has 2 sections, the top one is displayed normally, the bottom one (containing the nested iframe) is set with a height 0, and a padding-top max(60%, 326px). We don't support the usage of max() in that way (yet) as it's part of the CSS4 spec which is a work in progress (both the spec itself and the various implementations in browsers). The result is that the padding area used to display content (that's a design no-no by the way as it will not render in an accessible way) collapses to 0 and so is the iframe contained in it. It's there, just not visible.

See also bug #1519519 for min/max/clamp css value calculations. the site assumes all visitors support it -and- the weirdness of using padding area for content.