The HTML version of https://www.ecma-international.org/ecma-262/9.0/index.html contains references to assets which are 404 (listed below) - each of these includes kind of funky URL bits which I assume are probably the result of something missing in a processor somewhere or something?:
From referencing the latest standard it seems like the 4 images you're looking for are:
?
I'll let the folks at Ecma know that they're missing some images.
Three are now fixed:
The fourth is in progress:
The fourth missing image has been fixed. Thanks for your patience and all the best from a cold but sunny Geneva.