\stoppostponing to add two pages that interrupt the flow of normal text. When I was splitting the text manually, the interrupting pages used
\setupbackgrounds. Neither of these commands appear to work inside the postponing block: the setups are ignored within the block and use the setups of the page before where the postponed page is eventually placed. The postponing commands themselves are undocumented, making research that much harder. Additionally, the pages have different backgrounds, so changing a global definition attached to the postponing block doesn't help.
How do I define individual page setups for postponed pages?