Neowin[.]net/news/microsoft-releases-windows-10-cumulative-updates-with-ie-fixes
The linked article is good for listing the different update files [e.g. KB4522016 for win10 1903] but gives some wrong info. “The security update addresses the vulnerability [in Internet Explorer] by modifying how the scripting engine handles objects in memory.”
The update is not offered via Windows Update, even when you manually check for updates, & the page you get following the KB links Neowin provides states at the bottom that it’s only available in the Update Catalog, providing a link to that update in the catalog.
That said, while the update probably isn’t what folks are waiting for, and definitely is not the 2nd cumulative update for September, there may be an advantage to installing it… on my win10 Home 64 bit VM the Patch Tuesday update left a few GB of garbage behind that was not deleted using disk cleanup – running disk cleanup after this update found & deleted that trash from last time.