This is clearly an incomplete of the mappings supported within MSIX. Some additional folders can be seen in the mappings of the PSF/FileRedirectionFixuup (PathRedirection.h), but those exist because I ran into cases created by the packaging tool and added them myself. It is unlikely that this represents all possible mapping implemented by MSIX.
It would be good to have an updated official list.
Hi @TIMOTHY MANGAN, the list of folders on the page is the current VFS folder mapping supported on the OS without PSF. Now with PSF, you can extend that list to additional folders beyond the current VFS folder mapping. These additional folders are determined by the author of the PSF so we don't have an exhaustive list.