When viewing the On iPhone folder in Files, iSH is only available through the Locations area and FileProvider extension. Enabling UISupportsDocumentBrowser in Info.plist would make the documents directory available as well. This provides another means of sharing data with other apps, and it seems that apps have more flexibility when accessing data through that On-iPhone interface than with the FileProvider extension, although I don't know the specifics. I'm not sure how it affects 'themes' or what else the Documents directory is used for, but it seems like the ability to download a theme file from Safari directly into the themes folder without requiring a mount wouldn't be a bad thing.
When viewing the On iPhone folder in Files, iSH is only available through the Locations area and FileProvider extension. Enabling UISupportsDocumentBrowser in Info.plist would make the documents directory available as well. This provides another means of sharing data with other apps, and it seems that apps have more flexibility when accessing data through that On-iPhone interface than with the FileProvider extension, although I don't know the specifics. I'm not sure how it affects 'themes' or what else the Documents directory is used for, but it seems like the ability to download a theme file from Safari directly into the themes folder without requiring a mount wouldn't be a bad thing.